These adapters are designed to fit my Robinair vacuum pumps exhaust and attach to an oil mist filter that uses a KF-25 fitting. I got tired of having to exhaust my pumps out the window when drying my 3D printer filaments, so I bought an expensive filter from Amazon to mitigate the mist. https://www.amazon.com/dp/B07LBDYN5S?ref=ppx_yo2ov_dt_b_fed_asin_title. So far, this filter doesn't show any signs of misting. You will need a KF-25 clamp to attach it to the filter or other KF-25 arrangement. https://www.amazon.com/dp/B0D4JSQ7WT?ref=ppx_yo2ov_dt_b_fed_asin_title

The pumps I own are models 15150 and 15310. The adapter for model 15150 requires 3 M4 x 16mm socket head cap screws to attach it. It uses the rubber gasket that comes with the original exhaust fitting (523203). The adapter for model 15310 threads right on to the exhaust port on the pump body and reuses the O-ring that comes with the stock exhaust fitting.

I designed the adapters to print without supports, however the one for the 15150 isn't easy to print with the strong filaments required to make it robust. I have included a two piece adapter for that model that prints easily and just needs to be glued together before use. It has alignment features to make assembly go smoothly.

I have been printing these in ABS with 70% rectilinear infill and they seem to hold up well. Other filaments like PETG print fine and should hold up to abuse. Your mileage may vary.