Tech&Life Egg Shaped Stander Music Audio Loud Speaker Amplifier Silicone Rubber for Apple iPhone 4 / 4s / 5 - Green No external power needed,13 dB of volume amplifer Silicone Egg Shaped effectively enlarges music from your phone Unique design stand amplifier for Apple Phone Holds iPhone vertically and horizontally, functions well in hand-free mode Compatible with the following:iPhone 4 , iPhone 3G S , iPhone 3G