Makita is the leading manufacturer of professional power tools on the market. The B-66818 Impact Black Screw Guide is a magnetic screw guide, with 1/4" hex shank and a black coating to prevent rusting and corrosion, suitable for applications including screwdriving, joinery, assembly, fixings and more, for use with Impact Drivers. The B-66818 has a higher durability with a longer life than standard bits and works well with both 25mm and 50mm Impact Black screw bits.