I have a vacugrip and it grips the head by vacuum. You first cover your head with non sticking sports wrap (This wrap sticks to itself and not your skin). Then your install what they call a protector sleeve on. This is like a condom but much more heavy duty. Then you intsall the grip chamber and velgro ring just behind the glands on the shaft. Insert the tube and pull a vacuum. It can hold lots of weight and gave me what I consider to be an perfect stretch however I could only stay in it for 40 mins max because dispite the fact that you have protected the head with a wrap and contact sleave the head still goes cold and numbess starts.
However most stretch session I had in the begginning were great but after 3 months of using it my skin underneath the penis started to always get in the way and my lig stretches all become skin stretches and other times the sleaves would wear out and burst right when I held weight applied. The hole device was riped off my head and it all would happen so fast it would not only scare the shit out of me but felt like a huge bandage being pulled of my penis.
But when set up correctly the vacugrip was an effective holding device but I have now found out since being out Thundersplace that anything griping on the glands is dangerous and I do believe that I was loosing some sensitiivy in the head. It was just a sense at the time but now I now it was true.
I now have a Bib Hanger and I’m still experimenting. I believe there is a correct positon and setting for my new hanger but I have not got it yet, Where as the vacugrip was spot on the first time I put it on but its effectness did deminish but I suspect that’s because of the skin greating struck. Hence I have moved on to the Bib.