The heavy caps are either threaded or snap fit so that they will not pull off in use, and are castellated for greater impact. The flutes, grooves and body tapers on the pens, combined with the pewter-toned stainless steel pocket clip, provide a secure grip. With some basic instruction or knowledge, one can readily use the pens against an assailant or attacker to inflict notice, pain or injury thwarting an otherwise potentially defenseless act. And, they're just plain great writing instruments as well.