... ,1/4"hexagon screw driver bits,screwdriver bits 2.material:S2 STEEL,CRV STEEL 3.surface:sand blast or black 1 ... /4"hexagon screw driver bits,screwdriver bitsSpecifications 1. Material: S2, Cr-V ,6150, etc. 2. Different length is available(50mm ... special finishes be required by customers 4.Type:double head, non-magnetic and magnetic 5.Head types:PH,PZ,T,and so on ...