Captain O-Ring Ors/Orfs (For Flat Face Fittings), Buna 90 / Bn90-180 Piece Kit Includes high quality Buna Nitrile (90 durometer) o-rings Includes #4 (1/4" Flat Face), #6 (3/8" Flat Face), #8 (1/2" Flat Face), #10 (5/8" Flat Face), #12 (3/4" Flat Face), #16 (1" Flat Face), #20 (1-1/4" Flat Face), and #24 (1-1/2" Flat Face) o-rings Used in sealing ORS / ORFS Flat Face Hydraulic Fittings in hydraulic equipment. Also called O-Ring Face Seal Fittings, and SAE J1453 Fittings. High quality o-rings organized by size in a sturdy compartment box, with a life-size o-ring size chart featured on the front of the box to easily match up your ORS/ORFS o-ring sizes. The ultimate ORS hydraulic o-ring kit for your toolbox. Manufactured and Warrantied by Captain O-Ring LLC. Proudly assembled in the USA!