I do believe it could have been designed with a better taper and size to fit more shower units
It's true, the holder opening is too small.  Having a DIY shop, I used my spindle sander to enlarge and taper to make it fit well.  A person could file it out too.  Attaching to the wall depends on the surface.  The tile I have is non porous so I cleaned it and then lightly moistened the suction cup - wiggled and pushed lightly before activating the lever.  No problems here now.  I do believe it could have been designed with a better taper and size to fit more shower units.
Rating: 4 stars