So this is by far the most comfortable device I have found. 5.5 cm ring is just about perfect for me (6 cm can have testicles pop out of the ring, any smaller is painful). Like most guys experienced with this say - go smaller than you think possible. Smaller penis cage is more comfortable, although I find it just a little too tight diameter wise to the point it can be hard to urinate because the urethra is pinched. Shorter cages make for easier and less messy urination. The keys are ugly and not something to display around your keyholders neck or anything like that. But the lock is convenient for you as the chastity wearer because you don't need a key to lock yourself and it's silent and low profile. Anyway, I might try to order something custom based on the Swiss Holy Trainer with just slightly different dimensions. Any recommendations?