It is inserted between the bearing surface and tightening section when tightening machine screws or bolts. ISO standard.
[Material]
·Steel: highly corrosion resistant hot-dip coating steel plate
[Special Plating]
·Green Chromate / dacrotized / black chromate / tin cobalt / dark bronze color plating / hot-dip galvanizing / black nickel / chromate plating / parkerizing / trivalent black / 8 micron chromate yellow