Klein Tools' large flip impact socket adapter is a must have for all tradesmen. The 1/2 to 1/2 in square adapter is designed for use with the Klein Tools' small flip impact socket adapter (Cat. No. 66079) for dual-drive capability. When combined with Klein Tools' flip impact socket set, it provides even more versatility with five available socket sizes with which to work. Klein® 66078 Flip Impact Socket Adapter, 4140 Steel, Large, 3.125 L x 0.625 H x 0.625 W in