I was recently sent this device called the "Sidekick" which is media player holder to evaluate. I tried it out with my Ipod Touch and an old smart phone for my test. Please forgive me for the poor pictures since I had some issues with my normal camera and had to use the camera on my phone to take these. I will try and replace these pictures soon so you can get a better idea how the device works.
I used several different styles of guitars and neck arrangements to see how the device might deal with various string arrangements and angles. It held on tight to all the guitars I tried and the only thing I noticed was with heavier gauge strings it didn't seem to be as tight. With all the guitar related apps available this thing could really come in handy during practice sessions.
Front of package
Back of package
6 on a side hockey stick style neck
6 on a side strat/tele style neck
3x3 style neck
You can find more information and ordering information on their website. www.castiv.com