Text and drawings copied from TM9-1985-2 German Explosive ordnance 1953 :
Description: The igniter body houses a plunger assembly and has a baseplug containing a percussion cap. The plunger assembly consists of a movable cylindrical plunger to which is screwed a pressure head, the top of which is adjustable in relation to the top of the plunger, and a striker. The plunger rides in the guide, and is held in position by the pressure spring. The lower part of plunger is bored to recieve the striker assembly. The striker or firing pin is held in position within the plunger by the two steel balls which seat in holes in the plunger. The safety device is the pin, with a nut. The pin fits into hole and prevents the plunger from moving downward. To prevent the safety pin from accidentally falling out when the nut is off, a steel ball, under pressure from a spring, fits into a groove in the safetypin. Pressure on the steel ball can be varied by the means of the adjusting screw directly over it.
Operation: This igniter is armed by first removing the safety pin nut and then withdrawing the safety pin. Pressure on the pressure cap forces the cylindrical plunger downward against the resistance of the pressure spring. Two locking balls are then forced outward into the lower open space, releasing the striker. The striker driven by the striker spring, sets off the percussion cap.
Employment: Used to fire prepared charges of the type where pressure, as from heavy vehicles, can be readibly applied. It is also used as the main igniter in the heavy antitank mine.