... ROHS. 2. Materials: NBR, NR, FPM...etc 3. Use for all machines,size:50-630 SR:good resilience,ozone resistance ... tensile strength,good tearing property,heat resistance,abrasion resistance,oil resistance,acid resistance,alkali resistance,and good fire resistance.NBR ... packing:standards carton boxO RINGdurable in liquid material,mineral oil,lubricant and other different environmentmateria:SR,NBR,EPDM,NR ...