3pcs Screwdriver Socket Drill Extension Adapter 3 Pieces Hex Shank Drill Socket Screwdriver Extension Adapter 1/4" 3/8" 1/2" describe: Made of chrome vanadium steel for heavy duty impact drives. Heat treated, strong and wear resistant. The head has a spring to hold the socket securely for your impact driver or drill. you The ratchet can be replaced with a power tool, with a 1/4" hex shank. This set is perfect for an impact driver or drill and allows you to replace the ratchet with a power tool Specification: 1/41/450mm: 1/4 hexagonal handle-6.35mm square head 3/8 * 1/4 * 50mm: 3/8 Hex Shank - - 9.53mm Square Head 1/2* 1/4*50mm: 1/2 Hex Shank - 12.7mm Square Head 1 Piece (1/4" hex shank to 1/4" socket) 1-piece socket adapter (1/4" hex shank to 3/8" socket), 1 Socket Adapter (1/4" Hex Shank to 1/2" Socket) Note: Please allow 0.5-1 inch difference due to manual measurement. (1 inch = 2.54 cm)