Heavy Hex Slotted Nuts ,with different sizs , materials, standards and finishes . Heavy Hex Slotted Nutsstandard : JIS , DIN . AISI, GB .material : carbon steel , stainless steel , alloy steel .class: class4 . class 8, class10.9,class12.9. grade2,grade5,grade8,finish:plain , black oxide , blue zinc ,yellow zinc , black zinc , nickel and so on.