Professional tool for commercial or occasional use Manufactured from chrome vanadium steel for strength and durability 3/8" square drive so will fit any 3/8" drive ratchet / bars etc... Extra long bits (110mm total length) so ideal for access into those hard to reach awkward areas Metric sizes 4mm 10mm Spline / Triple square sockets. Triple square / spline / 12 sided sockets this limits the amount of wear on the corners of the fastener and the socket as you have more sides / teeth on the socket biting onto the item. Includes Sizes 4mm, 5mm, 6mm, 7mm, 8mm, 9mm and 10mm. Comes in a blow molded case for easy storage and transportation