6 Piece Portable Set includes the following sizes: 5mm, 6mm, 8mm, 9mm, 10mm, 12mm | Foldable, compact design stores 6 drivers inside | Slim Aluminum handle makes it easy to grip onto while driving nuts and bolts | Magnetic retention in 1/4" drive opening to hold insert bits Alloy steel nut driver shaft with a chrome nickel finish for durability | It's widely used in household DIY, auto parts, woodworking, professional machine repairing, etc.