With the versatile Böker Plus MPP you are prepared for all situations in life. The pen serves primarily as a high-quality writing instrument, of course, but can also save lives in extreme cases. In emergency situations, for example, the glass breaker can help to free injured persons from cars or the stable body can be used for Kubotan techniques. The black handle body with wide grooves is made of lightweight aluminium and fits comfortably in the hand. The stable clip keeps the MPP always ready to hand. It is compatible to Fisher Space-Pen refills #Pr4, to change the refills it is screwed apart with a left hand thread. This prevents unintentional disassembly of the pen when unscrewing the cap. The diameter of the cap is 13.9 millimeters.