Review on Convenient and Secure 2Pack Adhesive Phone Pocket for iPhone, Android, and All Smartphones - Black (Double Pocket) by Zachary Pete

Extremely slim design and soft to the touch. The adhesive is quite strong, especially since the back of my phone case is textured with narrow, deep grooves that run horizontally. So, pro tip for people who might have adhesion issues and if you don't mind damaging your smooth phone cases a bit, get a nail file or sandpaper (fine grit should do the trick ie 400-600 grit) and roughen gently a small area where the wallet will be placed. Wipe away any dust or residue with rubbing alcohol and allow to dry completely. For extra adhesion, take a hair dryer or glue warmer to your wallet before sticking it to your phone. Apply some pressure and you're done. I really like this wallet!