I've tried six or seven types of pump seals, invented some myself, and have never been satisfied with any of them. Most of them would let a ******** get ****** past the seal, and freeing such a ******** is often painful. Others were simply not tight enough to give a good seal, others were too tight. When this arrived I was skeptical because the opening was so small. I put it on a pump, put some lube on the sleeve, and allowed the vacuum to pull my ***** into the chamber. The sensation was better than any I have ever had with such a pump, and the blood flowed into my ***** quickly and effectively. I slipped a **** ring
on and removed the pump and was quite pleased with the results. The second time I used the sleeve, the material tore between the opening and the wall of the pump. I did not realize this until I tried to remove the pump from my *****... the soft material made a satisfactory seal for the pump even with the tear. Be careful with this sleeve as it is delicate; so not use the pump as a replacement for a ************ sleeve as this can cause the sleeve to tear; use sufficient lubricant at all times. As a seal this was the best seal I have ever used with a pump, and in fact it still works without the central portion that grips the *****. It worked much better with that portion, and I was disappointed the item was not more durable than it was. All the same, I plan on ordering a couple more of these, and just being more careful with them when I use them.