Introducing Button head swiveling couplers, your go-to solution for precise lubrication needs. These are useful with button head grease fittings commonly found on heavy machinery, agricultural equipment, and contractor's machinery. With a zinc die-cast body and a metal seal for enhanced wear resistance, these swivelling couplers are suitable for use on 5/8”(16mm) grease fittings with a pressure rating upto 3000 PSI. Recommended for use with hand-operated grease guns only.