My shower had two screwholes in the wall, about an inch vertically apart. (24mm to the civilised chaps.) Leftovers from a previously borked soap dish from a bygone era. The Pebble smartwatch makes a pretty fantastic waterproof remote for my shower tunes, but doesn't like constant exposure to hot water. And who wants to wash with a watch on, anyway? So. The mission was clear. Mount the pebble on the wall. Now. Off to the shower with Bon Jovi and ZZ Top, as god intended. Print files for this Thing are now hosted at YoumagineThis should work with one screw, two about an inch apart, or just some adhesive on the back. 3M's Command system would be good, I'd say. Mine's screwed for optimum awesomeness. Screwing in the shower? Highly recommended.