The Light Up armband has special feature: lights up for safety in the dark. Three light modes: steady, flashing, pulsing. Water resistant. Slot for key so its not tied to your shoe or bouncing in your pocket. Ample band length to fit any arm. Fits most smart phones up to 6" screen. Touch screen functionality. Earbud slots so wires are tidy during your workout. For first time use, pull plastic tab near battery.