This is a 4-Piece Push-On Pushnut set that provides a durable and pliable secure fastening solution. This item serves as a 5/8" Phosphate & Oil Impregnated, Pal, Push on Nut replacement. It is generally used as a wheel retaining nuts. for 5/8 inch shafts. Once Pressed on the end of your shaft or axle, they won't come off easily. They are easy to install with a Socket & a Hammer. Just tap them on and they are there to stay. These fit most Hand Trucks.n for 5/8" smooth shafts for attaching cart wheel to hand trucks and utility carts.