Collar for Ventilation Pipe

While installing our new cooktop with integrated ventilation, some way of fitting the odd square'ish pipe through the wall was needed. So I designed these.

An inside collar that can be fastened to the drywall using glue and screws, and an outside version that can be embedded in the masonry 

When both are in place (and ligned up) the ventilation pipe fits snugly through and can be removed and replaced if nedded.

The inside version is to large to fit on my printer, so split it in two (the two parts are identical)

Print from what ever, but ABS would perhaps be best.