There are numerous variables with respect to phone compatibility. First is the use of the magnetic input. The magnetic input works as a ‘mouse click’ or a double tap of your phone screen as a way of providing input to your phone. If your phone’s magnetic receptor is not located on the side of the exterior magnet, it will not work. As a work around, you can always reach through the nose hole and tap your screen. The second area of compatibility is the size of your phone. Currently the HTC One size is the largest that works. We are working on a V2 with wider compatibility for later in the year, but for now devices like the Samsung Note 3 do not work (unless you want to DIY a solution which is totally possible).