3-PC Magnetic Bit Holder Set Extensions 2.4" & 4"&6 " Quick Change 1/4" Hex Shank Applies to: pneumatic air grant, hand drill, rechargeable drill, electric screwdriver. Purpose: screwdriver and other tools used in extreme operating environments lengthen connection, Extensions in lengths 6", 4" & 2" for superior access for hard-to-reach fasteners