This magnetic screwdriver and bit set makes it easy to add and remove screws and bolts. The set comes with 20 hardened and tempered 8660 alloy steel bits held in place by a 1/4-inch magnetic bit holder built into the chrome-plated blade. The magnetic bit holder makes it easy and safe to put the bits where you want them, and the hardened and tempered steel bits are made to handle the hardest jobs. Technical Information:This 23 piece set contains:Screwdriver with 1/4" magnetic holderAdaptor 1/4" sq. drive x 1/4" hexagonMagnetic bit holder 1/4" (F) x 1/4" (M)4 plain slot bits size: 4, 5, 6 and 7mm3 cross slot bits: No.1, 2 and 33 PZ TYPE bits: No.1, 2 and 33 hexagonal bits size: 4, 5 and 6mm7 TX-STAR bits: T10, T15, T20, T25, T27, T30 and T40