The WK RnD Axe Series is a collaborative design between Master Bladesmith Daniel Winkler and skilled Sayoc Kali martial arts trainer Rafael Kayanan. The full-size model is the most tested and highly developed axe produced by Winkler Knives, and has been proven in combat applications by a Special Operations Force Team. It is a favorite among operators and servicemen who choose their own equipment. The handle design provides a standard grip position, as well as a secondary close quarter grip that was developed to emulate the feel of a handgun grip.