The Black Diamond Metric Grease Fitting Set 80 PCS gives you a ready assortment of durable metric fittings for maintenance and repair work. Each fitting is heat treated to SAE J534 specification, with the greasing end hardened to a minimum of 83 on the Rockwell 15N scale and a case depth of 0.005" to 0.009" for wear resistance. A ball check with heat-treated springs helps maintain a consistent seal and extended service life. The steel fittings are zinc plated for corrosion protection, and profiles and dimensions are accurately controlled to conform to SAE standards.