O ring sealing in NBR,HNBR,EPDM,Silicone,Viton Hardness:ShoreA60,70, ... :black,green,yellow,blue NSF,WRAS,TZW,W270,FDA ItemO ring Sealing DescriptionDescriptionWidely used in bathroom product, valve, faucet, machine, ... automobiles.Shore 60±5 ; 70±5AdvantageGood Ozone resistance, aging resistance, high/low temperature resistance, acid/alkali resistance, weather resistance, abrasion resistance ...