This is a 6 millimeter x 1 millimeter, taper metric thread, 45 degree, 0.81 inches grease fitting. These fittings have a ball check in the head to prevent dirt and grit from getting into the fitting, heavier wall thickness for extra strength, are zinc plated with a yellow passivated finish for maximum protection against corrosion, and have a stress relieved and tempered carbon steel spring. Every fitting is individually inspected and batch tested to 5,000 PSI and are designed to meet the demanding requirements of most automotive, agricultural, industrial, marine, truck, federal, and construction equipment needs.