BlueSpot 14 Pce Nut Driver Set (Metric & Imperial) The BlueSpot 14 Pce Nut Driver Set (Metric & Imperial) is manufactured from heat treated, chrome vanadium steel for increased durability, with a sandblasted finish to protect against corrosion. The 1/4" drive is ideal for use with power drills and electric screwdrivers and contains a full range of both metric and imperial sizes. The set is supplied in a robust clip for easy access and storage. Set Includes: 7 nut driver bits: 3/16, 1/4, 9/32, 5/16, 11/32, 3/8, 7/16 inch. 7 nut driver bits: 5, 5.5, 6, 7, 8, 10, 12 mm. Work belt storage clip. To activate the manufacturers lifetime guarantee, you will need to register the product on the Bluespot website within 30 days of purchase.