We have an RV with a nonmotorized roof vent in the bathroom. I am barely able to open it and my wife is not able to without assistance.  I went looking and found a few designs but they would not work with our vent knob and did not have a handle grip. 

So I designed one for our use. We have been using it for a few  years, someone at a campground recently noticed it and said I should be selling it. No interest in doing that, I gave them ours and am going to print a new one now that we are back home.  Figured might as well publish it in case anyone else wants one.

Printed in 95A TPU for impact resistance. Designed to fit onto ½ inch PVC waterpipe. I heated it a bit and forced it on .

The handle should not need supports as it is domed inside, The base will need support touching the buildplate.