These Carbon Steel Height Threaded Adjustable Leveling Glides are perfect for use on tables, desks, shelves, cabinets and more. The glides feature a male 5/16"-18 thread and aadjust1" up or down. The cups have a 2-1/4" diameter and are made of durable carbon steel with a black powder coat finish. Each package includes four glides and eight 5/16"-18 flat washers for installation.