You can find 2 different kinds of smartphones case, universal or specific for your smartphone model. The specifics one are created to be fixed in the helmet and support all the functions of the newest generation of smartphones like iPhone 5 and 6 or Android system like Samsung Galaxy 4, 5 and 6. For the universal you just need to know the dimension of your device. You can find different kinds of Bluetooth interphone, the basic with a simply connection with your phone, and the advanced with more options and vocal control of the device. The specific models are made to be fixed in your helmet and remain hidden, the control box can be fixed on the external part of the helmet.