Internal rings with tapered design. Maintain constant pressure to prevent slippage of axles, gears, and bearings inside machinery housing. Handy kit for shop toolroom or toolbox. On hand when needed saves time and money. Plastic compartment box is easy to store. The Precision Brand® 150 Piece Housing Ring Asst contains: 15 each of 1/2″, 5/8″, 11/16″, 3/4″, 13/16″, and 7/8″; 10 each of 1″, 1-1/16″, 1-1/8″, and 1-1/4″; 5 each of 1-3/8″, 1-1/2″, 1-5/8″, and 1-3/4″.