Impact o-ring for securing impact socket wrenches and impact screwdrivers. For impact socket wrenches from 6–16 mm and RECA impact adapter for bits (art. no.: 0700 121 163). Thickness: 4 mm Field of Application: For RECA impact extensions 1/2" and RECA impact adapters 1/2" x bits. Advice: Every impact socket wrench or every impact drive element must have a groove and a hole that must be locked with a securing connector pin and a securing O-ring.