IRWIN Tools 6-Inch SPEEDBOR Lock N' Load Quick Change Bit Holder (4935704) Each IRWIN quick-change bit holder features a chrome plated sleeve with a carbon steel body Bit extension has a patented jaw design with 6-flatted shanks to hold bits securely These bit holders use the Lock-n-Load system for 1-handed quick release 1/4-inch quick-change range now holds insert bits; magnetic for holding 6" overall length