The fuze has a selective arming time delay of 4 to 20 s, marked in 2 s intervals from 4 to 8 s and in 4 s intervals from 8 to 20 seconds. The striker is activated by inertia instead of impact.
Arming is effected by the vane arming assembly M772 through the rotation action of the flexible drive connected to the coupler drive assembly which reduces the high revolutions of the arming drive to a constant speed output of approximately 1800 revolutions per minute. The coupler drive assembly accepts the torque from the flexible drive shaft and transmits it to the attached tail fuze.
The fuze is made up of two main assemblies, the input drive housing assembly and the fuze body assembly.
This fuze may be used for impact and impact-delay application in conjuction with nose fuze M904 and forms the tail component of the fuzing system for unguided and guided bombs.
A safety pin prevents the vanes of the arming drive assembly from rotating. An instruction label attached to a red tag and safety pin states that after the arming wire has been inserted in the drive assembly the safety pin is to be removed, and replaced if the bomb is not dropped. The safety features of the fuze are the same as for the nose fuze M904 except that a white stripe appears in the large inspection windows at all arming delay settings.