Work on my 2.25 diameter pump and feels great!
Very soft and supple, to the point that there wasn't a lot of sensation from the tunnel. Trimmed the inner sleeve off so that penis head could exit the top of the tunnel, be pulled back in, and then let vacuum pull it out again. That was OK.
Much nicer to use with pump, only problem is gets sucked into the pump. Base is much smaller than other models. I have 2" wide base and ordered (S) 2-2.25" and base is just too thin. Good for masturbator only.
The silicone is soft and pliable as expected. The silicone around the outer edge that mates against the vacuum jar should be made of a stiffer material so that it will not collapse and be drawn into the vacuum jar. The length of the silicone is perfect, along with its ridged passageway.
First use. Sleeve so stretchy that it clogged the vaccum port and burned up my 200 dollar pump