As everything described in the features, diameter was a bit snug, but bearable, no leaks and deffinatly created a constant vacumn . Make sure to be somewjhat generous with the lube, worked with with ball pumping also.
Working great! Charges fast and lasts!
I tried this once and it was painful, too small, difficult to use. I couldn't find the value in it.
The opening of the pump is a little too wide. The flimsy donut slides inside the pump too easily. If I use the pump without the donut, it sucks one of my balls inside, which is kinda painful, I had to order a better quality silicone donut to use with this pump.
This pump works great. Creates size and fullness. Feels erotic. Makes a lot of pre cum instantly. Get an aftermarket ring. The enhanced male has them for sale.