Add another fitting. Basically the chastity device is ready. It was not difficult, was it? You can try it on now. If the gap is too narrow to pull the testicles through it – release the screw, so the clamps can easily rotate around it. Usually I insert the testicles first then push the penis into the tube. But you method can be different, of course.
Nice idea; I’m going looking for some large clamps, the 50mm rings on the commercial ones are too small. BTW the images don’t work in Firefox browser