... available. Description of Aging-proof Flat O-ring with High Quality:1. Materials: can be NR flat o-ring, HNBR, Buna, ... color codes. 6. Processing: all manufacturing processes are complied with ISO9001:2008. Please contact us if you need detailed ... FDA, NSF, KTW, WRAS, LFGB, etc. 8. Applications: automobile flat o-ring, electrical appliance, mechanical, industrial, construction, household, medical and ...