The standard grease coupler is for use with most hand-operated grease guns and equipment, fits all 1/8 inches NPT threads, is rated for 4, 500 PSI maximum operating pressure, has a built-in spring-loaded ball check valve that prevents leak, pressure loss and lubricant backup. It has four hardened steel jaws for a superior seal, longer life and precision fit. The slight pushing action snaps jaws onto fittings, small outside diameter permits easy contact with recessed fittings, knurled body and easy flats for easy installation and removal, and is zinc plated for maximum protection against corrosion. Lumax is a manufacturer of lubrication and fluid management products. Our products, including grease guns, manual and electric pumps, funnels, drains, grease fittings, filter wrenches, and accessories, are built to the highest standards and incorporate many proprietary features. Lumax's mission is to provide professionals and consumers with innovative and high-quality products to get the job done right. Product development at Lumax goes beyond the physical product, to a deeper understanding of the end-users' needs. Engineered with the "user-in-mind, " Lumax products are built to the highest standards and incorporate many unique features that make work easier, faster and cost-effective. We have a passion for the design process. We listen to our customers and their ever-expanding requirements. Our unique products lead the field in design, quality, and performance.