This is a blast gate for a 4 inch (100mm) shop dust collection system.
The design includes parts to allow you to connect the blast gate to a 4 inch hose or to the 4 inch dust port on your equipment.
Use the OD part to connect to a dust collector hose and the ID part to connect to the machine or other dust collector accessory (e.g. Y fitting).
I used OD on one side and ID on the other so the gate would attach to a Y fitting and a hose.
I printed this using a 0.8mm nozzle to reduce my printing times.
I printed mine in PLA because that I what I had on hand. It would probably be better to print in PETG or even ABS.
Holes are sized to fit 1/4" hardware. I used 1/4-20 x 1" bolts. I also used washers to prevent damage where the nut would tighten against the PLA
The gate has a retaining bump on it to prevent it from coming all the way out of the assembly when you open it. You will need to put the gate in during assembly, before the bolts are tightened down.