Includes a pack of four replacement blades for the Crain/Gundlach No. 174 Instant Repair Tool used to cut circular holes in carpet for repairs. The four blades in this pack can replace all four blades in the tool if desired. Blades have a slot that accepts the blade screws on the tool. Blade dimensions: length: 1.035″, width: .50″, thickness: .020″..