The Colt Silicone Sleeve is a bit of a non-starter. It's not bad, it's not fantastic - it simply is. Made of thin silicone, it forms a lip around the base of the pumping cylinder that allows an airtight gasket to form when the penis is inserted through the opening. Pretty basic science, really.

Only a few things distinguish this sleeve from most others. First among these are the four "petals" or "leaves" of the tip of the inner sleeve, where the penis exits into the vacuum chamber. At first, they look like they may create a better vacuum within the cylinder or allow a wider variety of sizes of penis, but in function they simply serve little purpose - the circle formed at the base of the petals forms the actual seal and isn't affected by the presence of the petals. They simply look like a more sophisticated mechanism - no points added or subtracted.

The second distinguishing factor from every other thin pump-sleeve on the market are the ridges in the silicone. Again, I have no idea why they are there - perhaps to trap more lube against the penis to create a better seal? In my experience, they really didn't do much to improve the airtight seal, as air leaking at the penis wasn't really an issue. I'm tempted to give a demerit for these rings, as they could potentially be irritating on removing the vacuum-inflated penis, but I didn't experience this, so I won't lower marks for theoretical possibilities.

Perhaps the only genuine distinguishing factor is that the sleeve is clear. This also isn't a huge issue one way or another, but at least you can see how much member hasn't been sucked up into the cylinder.

Where I do take off points is the sleeve isn't very effective at this size. Because the inner sleeve extends so far up into the chamber, much less of the penis can actually be vacuumed (almost sounds like spring cleaning - caution folks, do not hook up a pump or a pumping sleeve into the family vacuum). On top of this, because the sleeve is thin and stretched over a large area, it tends to get sucked in with the penis, as there isn't enough material on the outside wall of the cylinder to anchor it in place. Were this a smaller size, hands could help hold the seal in place, but at 2.75" in diameter, it really isn't feasible unless you have enormous hands. And if what I've heard about big hands is true, you probably don't need this product anyway.

So in reality, it's a basic pumping sleeve which happens to be clear silicone. To be truly effective, you need to add-on either a pipe clamp, or some other form of anchoring, around the outside of the sleeve to hold it in place during a pumping session, or else the air will leak out.

Here are the critical details - the outer diameter is approximately 3" to make it clear the outer diameter of the Colt 2.75" pump cylinder. The inner sleeve tapers from approximately 1.5" in diameter at the outer opening to about 1" in diameter at the opening of the petals. The total length of the insertion cone is slightly less than 2", and the outer sleeve is roughly the same length as the inner sleeve. The sleeve is advertised as silicone, which is most likely not relevant - yes, it can be boiled to be sterilized, but most likely it won't come in contact with bodily fluids unless you have open wounds on your penis. In which case, you probably should put the sleeve and pump away for a little while...

Again, all in all an average, acceptable product. I wish Colt had included some means of better securing the sleeve to the cylinder, but a trip to the hardware store could fix that. Overall, 4 stars given for being adequate, if not stellar.