... /high carbon steel) Stainless steel, Aluminum alloy,Surface Treatment: Chrome plating, Silver plating, Zinc plating, Nickel plating, Tin-plating ... Washers/Gaskets, Check rings, Pins, Rivets and etc. 2. by head types Flat, Oval, Binding, Pan, Round, Truss, Button, PF ... washer, Cheese, Countersunk, Fillister, hexagon, Hexagon washer head, Hexagon socket button head and etc. 3. by type of drive inserts ...