The water-based power of this pump is for users measuring up to 7 inches when erect and accommodates a girth up to 6.5 inches. Once filled with warm water, the pump seals against the body. For best results, start with 3 five-minute sessions per use (1-3 months).
The sizing guide actually held true for me — I'm right around 6.5 inches in girth and the wide fit seals without pinching. Suction stays solid the whole session as long as I get a good seal at the base first.
The warm water fill makes a huge difference compared to the dry pumps I've tried — the seal holds tight and there's zero discomfort. Being on the wider side, I was worried about fit, but the 6.5 inch girth allowance is no joke. Been using it about three weeks and the results speak for themselves.
Wasn't sure the girth would work out since I'm right at the 6.5 inch limit, but the seal holds perfectly once it's filled with warm water. The clear barrel is a nice touch too, lets you actually see what's going on.