Nitrile - Commercial Grade Black - 60A Rubber Sheet - Buna Rubber - 1/2" Thic. nitrile butadiene nitrile rubbers nitrile material gasket nitrile buna gasket nitrile rubber gaskets buna chemical compatibility buna 70 buna elastomer buna-n chemical resistance buna sheet buna n sheet nitrile 60 rubber black black rubber sheets rubber