The Cal-Van Tools Versa Drive 2 in 1 adapters work with cordless or electric drills to allow the user to switch between bits and sockets without the hassle of changing adapters. The 3/8" adapter has a 1/4" hex built in to the drive the 1/2" drive has a 5/16" hex. To use, use a socket and then a bit without taking the time to loosen the chuck. These items are rated for use up to 167 ft-lbs of torque. the shank of these adapters is 1/4".
