Weld-on wrench hex that fits a 1 5/8" outer diameter tube. Made with steel, has a 1.640 inner diameter, and fits a 1 7/8" wrench. QA1 offers Weld-On Wrench Hexes that can be used in place of a hex style tube adapter. Simply use the smooth style tube adapters and slip the weld-on wrench hex over the tube. Weld it to the tube where it is most convenient for easy adjustment.