This product is relatively cheap and fun to see what a pump is like.
While you can easily place it against your crotch, pump away and achieves a decent erection, when my erection hits about 6.5-7", the pump oddly seems to 'lose pressure'. You can hit the 'release' button and no 'pressure' is removed.
If at that point, you pump it more with the hand pump and if you hit release immediately after; yes, some pressure is released. Leave it alone for 15s and nothing happens. So basically, even with a fairly raging erection which you'd think would cause a tight seal at the base, this device leaks pressure fairly fast/badly.
So you need to pump at least every 3-5s to maintain pressure and faster than every 3s to gain pressure.
As the pressure gets higher though, it takes longer for the pump bulb to fill and eventually I think you can't get much over 1.2 PSI maybe at most. It's hard to know how much suction your getting as there's no pressure valve with this pump.
I guess I can't argue with the price but the product is cheaply made(bad suction/seal + loses pressure). If you are serious about penis pumps, stay away from this penis pump and aim for a better one /w a pressure gauge that uses a gun-style pump and not ball-pump.