The SawStop Inline Router Table comes with a fence that attaches via a 2 ½" dust hose to the main 4" dust port under the table. But when not using the fence, a lot of suction gets wasted, so it is useful to cap the 2 ½" Y-split of the port.
This is just a 2 ½" (63mm) diameter circle extruded 15mm high. Includes Fusion 360 file.
The author marked this model as their own original creation.