The 106-AC easily adapts the #106 Work Tray or PTH-1 Paper Towel Holder to fit 35mm-37mm upright tubes on PCS-9 Repair Stands, as well as 2003 and newer PCS-1, PCS-4, PCS-4-1, PCS-4-2 Repair Stands. Features: Fits 1-3/8" tubing Easily adapts a PCS-1, PCS-4 or PCS-9 to accept the 106 Work Tray or PTH-1 Paper Towel Holder Note: The 106-AC will not fit the 1-5/8" tubing of the lower weldment of these stands