Shop-Vac coupler (37m ID)
I have a Shop-Vac wet-dry vacuum that has a hose end that works great with the accessories it comes with, but I haven't been able to connect it to tools like my Skil Router Table vacuum port because both ends are the same size. This coupler helps to connect the hose if the other end is the same diameter.
Nothing special to print it—it's just a tube.
This object was made in Tinkercad. Edit it online https://www.tinkercad.com/things/0ri7uR04UjT