They appeared to be as advertised. Fortunately have not had to use one yet but I'm counting on it to work when I need to if that ever happens.
I like the simplicity of it in that one suction of the pump could dislodge what's choking someone. And if another suction is needed, bringing the pump back downward, doesn't force air into the choker, but is released thru the bottom sides.
I'm not sure though, whether victims can use this on themselves. And I perhaps should place it hanging in the kitchen area - instead of on top of my bedroom chest.
Manuel
Haven't had to use it yet so can't really evaluate.. Hope I never have to !
Have put one in each car and have one here at home.