I have just got a copy of the 12a, item no 413261233 on dh gate, It is quite hard to get on but once on it is very secure, I do think my penis is about 3/8 to 1/2 an inch to short for this device as it seems to be pulling on my PA a little to much, I will give it an hour or 2 to see if it settles, my penis is about 1 3/4 inch when soft and my balls do not hang low normally so my penis is stretched tight over my balls when the glans are locked in to the head cage and my penis is trying to force my balls apart. I dont think I could get an erection in this device the way the penis is stretched and pointing downwards, I also dont know how comfortable it will be with my balls spread as much as they are, only time will tell but I do think if I was little longer it would be perfect.