Extension , 12 In/ OVERALL LENGTH: 12.00 INCHES NOMINAL ACCESSORY COMPONENTS AND QUANTITY: 1/8 INCH HEX KEY SPECIAL FEATURES: 1/4 INCH HEX SHANK;DRILL BIT SECURED BY 2 INTERNAL SCREWS FUNCTIONAL DESCRIPTION: FOR USE WITH 1/4 INCH HEX SHANK BITS, NOT INTENDED FOR USE WITH QUICK RELEASE SHANK DRILL BITS MATERIAL: STEEL