They certainly work -numb things quite a lot so you will lose some sensitivity but that is rather the "point" in using them over normal condoms.
Great to use for when you do want to last longer, certainly the wife didn't complain (well, save a little moaning).
These are just, wow. Does what it says in the box. I’m not normally a man to use anything different than standard Durex but I though why not give these a try and see if they work. They work! Maybe a little more than what was required but that may of just been me. But my other half was significantly pleased with the results.