Top positive review
these are the best suction cup hooks I've tried
Reviewed in Australia on 17 August 2019
these work really well, make sure you clean the surface (glass is best) with isopropyl alcohol to remove any residue/grease/oils which will make suction cups not work as well - especially inside a shower, otherwise they will simply fall off after a while
Have stuck one up for months and has not fallen (holds up a small caddy that holds a razor, wash scrubbie thing and a brush - I reckon less than 1kg total)
I have mine inside the shower on the shower glass, but well out of the way of direct water splashing/running on it. Steam hasn't affected it, not sure if excess water running onto it will.