Features:  1. They are made of high-speed steel material, and forging by high temperature quenching. Fastening,  rustproof, high efficient and durable. And High accuracy.  2. A number of different sizes to meet different needs. The 20-Piece tool set includes: 8 Bits (2 each: PH0, PH1, PH2, PH3);  8 Flathead Bits (2 each: 1/8" 3.2mm, 5/32" 4mm, 3/16" 4.8mm, 1/4" 6.3mm); 2 Countersink Bits ( 3/32" 2.4mm, 1/8" 3.2mm);  1 Allen Wrench; 1 Double-headed Drill Driver.  3. Easy to Replace: Easily switch between bits in seconds. Simple and practical.  4. Swivel head flips & locks from drilling to driving.Satisfied for DIY and woodworking with your own power drill.  5. Universal hex shank diameter is 6.35mm, hex handle design make clamping more stable.   All tool sets contained in a sturdy, folding plastic case for easy storage and portability.     Specifications:  Material: HSS  Color: As Shown  Function: punching, chamfering countersunk, screw tightening  Package size: (approx) 19.5x7.8x4.3cm    Package Included:  1 PC X Double-headed Drill Driver  8 PCs x Bits  8 PCs x Flathead Bits   2 PCs x Countersink Bits  1 PC X Allen Wrench  1 PC X Yellow Storage Case    Note:  1. Due to the light and screen difference, the item's color may be slightly different from the pictures.  2. Please allow 0.5-2 cm differences due to manual measurement.  3. The products are not suitable for the following materials: iron plate, glass, stainless steel.