My Quote Request
5999-01-351-7239
20 Products
MDU3-8547-25
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
DATA DELAY DEVICES INC
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
5429426
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013515600
NSN
5999-01-351-5600
5429426
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013515600
NSN
5999-01-351-5600
MFG
NAVAL SEA SYSTEMS COMMAND
Description
BODY STYLE: 37A EXTRUDED
MATERIAL: ALUMINUM OR ALUMINUM ALLOY
MOUNTING FACILITY TYPE AND QUANTITY: 16 UNTHREADED HOLE SINGLE MOUNTING FACILITY
OVERALL HEIGHT: 1.340 INCHES NOMINAL
OVERALL LENGTH: 8.850 INCHES NOMINAL
OVERALL WIDTH: 5.350 INCHES NOMINAL
SURFACE TREATMENT: ANODIZE
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-A-8625,CLASS 1,TYPE III MIL SPEC SINGLE TREATMENT RESPONSE
UNTHREADED MOUNTING HOLE DIAMETER: 0.162 INCHES MINIMUM AND 0.182 INCHES MAXIMUM SINGLE MOUNTING FACILITY
Related Searches:
7403-04FR-09
MOUNTING PAD,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013515601
NSN
5999-01-351-5601
7403-04FR-09
MOUNTING PAD,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013515601
NSN
5999-01-351-5601
MFG
BERGQUIST COMPANY THE
Description
BODY STYLE: 20B DISK
COLOR: GRAY
MATERIAL: GLASS FIBER AND RUBBER SILICONE CLASS Q
MOUNTING FACILITY TYPE AND QUANTITY: 3 UNTHREADED HOLE SINGLE MOUNTING FACILITY
OVERALL DIAMETER: 0.390 INCHES NOMINAL
OVERALL HEIGHT: 0.009 INCHES NOMINAL
UNTHREADED MOUNTING HOLE DIAMETER: 0.040 INCHES NOMINAL SINGLE MOUNTING FACILITY
Related Searches:
HW1-00255-001
MOUNTING PAD,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013515601
NSN
5999-01-351-5601
HW1-00255-001
MOUNTING PAD,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013515601
NSN
5999-01-351-5601
MFG
MICROSOURCE INC.
Description
BODY STYLE: 20B DISK
COLOR: GRAY
MATERIAL: GLASS FIBER AND RUBBER SILICONE CLASS Q
MOUNTING FACILITY TYPE AND QUANTITY: 3 UNTHREADED HOLE SINGLE MOUNTING FACILITY
OVERALL DIAMETER: 0.390 INCHES NOMINAL
OVERALL HEIGHT: 0.009 INCHES NOMINAL
UNTHREADED MOUNTING HOLE DIAMETER: 0.040 INCHES NOMINAL SINGLE MOUNTING FACILITY
Related Searches:
2051-7861
GASKETING MATERIAL,CONDUCTIVE
NSN, MFG P/N
5999013516254
NSN
5999-01-351-6254
2051-7861
GASKETING MATERIAL,CONDUCTIVE
NSN, MFG P/N
5999013516254
NSN
5999-01-351-6254
MFG
KRITECH CORPORATION
Description
GASKETING MATERIAL,CONDUCTIVE
Related Searches:
ZP20707
GASKETING MATERIAL,CONDUCTIVE
NSN, MFG P/N
5999013516254
NSN
5999-01-351-6254
ZP20707
GASKETING MATERIAL,CONDUCTIVE
NSN, MFG P/N
5999013516254
NSN
5999-01-351-6254
MFG
ZERO MANUFACTURING INC . DBA ZERO CASES
Description
GASKETING MATERIAL,CONDUCTIVE
Related Searches:
82-22033
SHIELDING GASKET,ELECTRONIC
NSN, MFG P/N
5999013516368
NSN
5999-01-351-6368
MFG
TECHNICAL WIRE PRODUCTS LLC DBA TWP
Description
APERTURE LENGTH: 1.920 INCHES NOMINAL
APERTURE WIDTH: 1.470 INCHES NOMINAL
BOLT HOLE QUANTITY: 4
COLOR: GRAY
CROSS-SECTIONAL HEIGHT: 0.040 INCHES NOMINAL
CROSS-SECTIONAL SHAPE STYLE: F89 WIRE AND COMPOSITION
ENVIRONMENTAL PROTECTION MATERIAL LOCATION: THROUGHOUT RF SHIELDING GASKET
HOLE DIAMETER: 0.136 INCHES NOMINAL
INSIDE CORNER RADIUS: 0.370 INCHES NOMINAL
MATERIAL: NICKEL ALLOY 400 EMI/RFI CONDUCTOR RUBBER SILICONE CLASS Q ENVIRONMENTAL SEAL
MATERIAL DOCUMENT AND CLASSIFICATION: AMS-4182 ASSN STD SINGLE MATERIAL RESPONSE EMI/RFI CONDUCTOR ZZ-R-765, CL 3, GR 30 FED SPEC SINGLE MATERIAL RESPONSE ENVIRONMENTAL SEAL
OUTSIDE CORNER BEVEL LENGTH ALONG LENGTH: 0.173 INCHES NOMINAL
OUTSIDE CORNER BEVEL LENGTH ALONG WIDTH: 0.173 INCHES NOMINAL
OVERALL LENGTH: 2.200 INCHES NOMINAL
OVERALL WIDTH: 1.750 INCHES NOMINAL
STYLE DESIGNATOR: B12H NON-CIRCULAR
Related Searches:
E8810-1
SHIELDING GASKET,ELECTRONIC
NSN, MFG P/N
5999013516368
NSN
5999-01-351-6368
MFG
SIMMONDS PRECISION PRODUCTS INC. DBA SENSORS AND INTEGRATED SYSTEMS
Description
APERTURE LENGTH: 1.920 INCHES NOMINAL
APERTURE WIDTH: 1.470 INCHES NOMINAL
BOLT HOLE QUANTITY: 4
COLOR: GRAY
CROSS-SECTIONAL HEIGHT: 0.040 INCHES NOMINAL
CROSS-SECTIONAL SHAPE STYLE: F89 WIRE AND COMPOSITION
ENVIRONMENTAL PROTECTION MATERIAL LOCATION: THROUGHOUT RF SHIELDING GASKET
HOLE DIAMETER: 0.136 INCHES NOMINAL
INSIDE CORNER RADIUS: 0.370 INCHES NOMINAL
MATERIAL: NICKEL ALLOY 400 EMI/RFI CONDUCTOR RUBBER SILICONE CLASS Q ENVIRONMENTAL SEAL
MATERIAL DOCUMENT AND CLASSIFICATION: AMS-4182 ASSN STD SINGLE MATERIAL RESPONSE EMI/RFI CONDUCTOR ZZ-R-765, CL 3, GR 30 FED SPEC SINGLE MATERIAL RESPONSE ENVIRONMENTAL SEAL
OUTSIDE CORNER BEVEL LENGTH ALONG LENGTH: 0.173 INCHES NOMINAL
OUTSIDE CORNER BEVEL LENGTH ALONG WIDTH: 0.173 INCHES NOMINAL
OVERALL LENGTH: 2.200 INCHES NOMINAL
OVERALL WIDTH: 1.750 INCHES NOMINAL
STYLE DESIGNATOR: B12H NON-CIRCULAR
Related Searches:
3071203204-01
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013516452
NSN
5999-01-351-6452
3071203204-01
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013516452
NSN
5999-01-351-6452
MFG
GE AVIATION SYSTEMS LLC DBA GE AVIATION DIV INFORMATION SYSTEMS - GERMANTOWN
Description
DESIGN CONTROL REFERENCE: 3071203204-01
III END ITEM IDENTIFICATION: AIRCRAFT MODEL F-14
MANUFACTURERS CODE: 86360
THE MANUFACTURERS DATA:
Related Searches:
98234
CLIP,ELECTRICAL
NSN, MFG P/N
5999013516979
NSN
5999-01-351-6979
MFG
SEARS ROEBUCK AND CO. DBA SEARS DIV SEARS COMMERCIAL
Description
CLIP,ELECTRICAL
Related Searches:
A349A355-101
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013517135
NSN
5999-01-351-7135
A349A355-101
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013517135
NSN
5999-01-351-7135
MFG
KEARFOTT CORPORATION DBA KEARFOTT DIV GUIDANCE AND NAVIGATION DIVISION
Description
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
Related Searches:
A203A493-01
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013517136
NSN
5999-01-351-7136
A203A493-01
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013517136
NSN
5999-01-351-7136
MFG
KEARFOTT CORPORATION DBA KEARFOTT DIV GUIDANCE AND NAVIGATION DIVISION
Description
III END ITEM IDENTIFICATION: 6605-01-234-5840 INERTIAL NAVIGA
MOUNTING FACILITY TYPE AND QUANTITY: 2 UNTHREADED HOLE SINGLE MOUNTING FACILITY
SURFACE TREATMENT: CHROMATE
UNTHREADED MOUNTING HOLE DIAMETER: 0.0974 INCHES MINIMUM AND 0.0994 INCHES MAXIMUM SINGLE MOUNTING FACILITY
Related Searches:
A349A352-102
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013517137
NSN
5999-01-351-7137
A349A352-102
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
NSN, MFG P/N
5999013517137
NSN
5999-01-351-7137
MFG
KEARFOTT CORPORATION DBA KEARFOTT DIV GUIDANCE AND NAVIGATION DIVISION
Description
HEAT SINK,ELECTRICAL-ELECTRONIC COMPONENT
Related Searches:
00T398
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
KAPPA TECHNOLOGIES INC.
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
85151-05
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
DLA LAND AND MARITIME OPNS SUPPORT GROUP STANDARDIZATION UNIT
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
95-31-025
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
ESC CONTROL ELECTRONICS LLC DBA CONTROL ELECTRONICS DIVISION OF FIL-COIL
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
DSP151-05
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
RHOMBUS INDUSTRIES INC
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
L-15-454
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
JBM ELECTRONICS INC
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
M447-0025-M3
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
BEL FUSE INC
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM
Related Searches:
MDU3-6547-25
DELAY LINE
NSN, MFG P/N
5999013517239
NSN
5999-01-351-7239
MFG
DATA DELAY DEVICES INC
Description
ATTENUATION IN DECIBELS: NOT RATED
BODY DEPTH: 0.260 INCHES MAXIMUM
BODY LENGTH: 0.800 INCHES MAXIMUM
BODY STYLE: 1 RECTANGULAR
BODY WIDTH: 0.400 INCHES MAXIMUM
DELAY TIME VARIATION PER DEG CELSIUS: NOT RATED
FREQUENCY BANDWIDTH: NOT RATED
FREQUENCY RATING: NOT RATED
III INCLOSURE TYPE: HERMETICALLY SEALED
INDIVIDUAL SECTION QUANTITY: 3
INPUT IMPEDANCE RATING: NOT RATED
LONGEST VERTICAL DISTANCE BETWEEN MOUNTING CENTERS: 0.300 INCHES NOMINAL
MATERIAL AND LOCATION: PLASTIC, MIL-M-14, TYPE SDG-F CASE OR PLASTIC, EPOXY CASE
MOUNTING FACILITY: PIN
MOUNTING FACILITY QUANTITY: 8
OPERATING TEMP RANGE: -55.0 TO 125.0 DEG CELSIUS
OUTPUT IMPEDANCE RATING: NOT RATED
PULSE RISE TIME RATING: 4.0 NANOSECONDS
SECTION DELAY TIME: 25.000 NANOSECONDS NOMINAL SINGLE SECTION
SIGNAL DELAY METHOD: LUMPED CONSTANT
TERMINAL TYPE AND QUANTITY: 8 PIN
VOLTAGE RATING: 4.500 VOLTS MINIMUM AND 5.500 VOLTS MAXIMUM