It holds it tight without the stretch material. The stretch material holds it rock solid. The best part for me is that it does not interfere with anything on the bike. It allows a 1 ft charging cord to be plugged in as well while riding.That's certainly an interesting mount, never really seen one before. How tight does the stretch material hold the phone? My biggest fear when it comes to mounts is to see my phone flying away after a few bumps and high speeds.