The 1707.2 Tool Tray Collar is an adaptor that allows both the PRS-20 and PRS-21 stands to accept installation of 106 Work TrayThe collar fits tubing 1-5/8` in diameterReplaces the collar on the PRS-20 and PRS-21 *Will not duplicate or replace the 106-AC accessory collar used on the PCS model standsUPC/EAN/GTIN: 763477014702