The Swivel Coupler will fasten from 1-1/4" pipe (1.660" OD) to 2.050" OD truss tube. The Swivel-Coupler has the wide wing nuts for fastening the clamp to the pipe or tube. The Swivel Coupler can be locked into a 90 degree fixed coupler by adding an optional 7/32? × 2? spirol pin (see Coupler Spare Parts). The Swivel Coupler is available with a Steel Wingnut(SW) or Stainless Steel Hardware (SS) option.