... certificate: ROHS. 2. Materials: NBR, NR, FPM...etc 3. Use for all machines,size:50-630 O RING1.Product/Service(We Sell ... ): O-rings,U-type loops,Y-type loops,customized rubber items2.Material NR ... :2000; SGS,PAHS,LFGB,ROHS,FDA,etc4.Size: customized5. Color: all available6.package: 5000 pcs/bag, 10000pcs/bag, or customized7. QC ...