Heavy Duty Titan Kubotan Self-Defense Tool. This is not your average kubotan. The BOKER PLUS Waves MFS Titan Kubotan Silver is designed by Rainer Wenning, the Waves MFS serves multiple purposes. For one, it is, according to Rainer Wenning's interpretation, a palm stick that makes a safe and secure tool in a self defense situation. Consequently, Rainer calls his design a "physio-tactical product". Diameter: 22mm. Overall length: 6". Weight: 5.5 oz.