Goodway Triangular Scraping Tube Cleaning Tools are used for removing heavy scale deposits in ferrous, straight tubes 1/2"-3/4" (12.7-19mm) I.D. These high quality tools dig into scale while it rotates, scraping off deposits as they pass through the tube. They can only be used in a clockwise direction and cannot be used in internally enhanced tubes. Adjustable to a 1/4" range. Select tube I.D. for sizing.