Combination screw

This combination screw for cross outside hexagonal screw, with iron material is low carbon steel to production, color can be electric blue white zinc plating, can also be electric environmental color blue white zinc. The screw to wear a ball pad, another flat pad. Then rub tooth. This will happen play mat peace falls off phenomenon. Screw in the assembly of a good prevent slippery effect, moreover after combination of medium carbon steel screw plating is a not easy to rust. The combination screw performance good, cheap, is used extensively.