Snap-on Industrial Brand JH Williams 3/8-Inch drive hand impact driver is specially heat treated for impact use to provide long life, safety, and durability. It features ball socket retention for fast socket changes and is ideal for loosening screws that cannot be loosened with an ordinary screwdriver. The impact driver is struck with a hammer to provide turning power. The hammer blow forces the bit into the screw head to reduce stripping. The hand impact driver can be used with all 3/8-Inch drive sockets.