Needed this for my miter saw since the OEM catch bag is marginal at best. Designed for a Bosch 5312 compound miter saw & shop-vac brand vacuum.
Inlet is 38mm ID with a slight taper. Outlet is 58mm ID with a similar taper. It should yield a decent slip fit from the saw to the shop vac hose.
The author marked this model as their own original creation.