For use with Short Action Customs MODULAR ACTION WRENCH HEADS. After extensive torture testing, Short Action Customs manufactured wrench bodies out of 4140 Alloy Steel with a super hard heat treat. With their unique modified 3/8a ^2 square drive interface is tool-less and offers super quick wrench head changes. On the back end, Short Action Customs have a standard 5/8a ^2 Hex to work with any standard 6 point or 12 point socket. With a nominal .685a ^2 body diameter, it works with a large array of actions. Short Action Customs Guarantee At Short Action Customs, they are only concerned with making the best products. The modular action wrench comes with a lifetime gua Mfg: Short Action Customs