This style is small size and light weight. More secure and reliable, It can be placed in your pocket and can be used at any time to quickly charge the electronic equipment anywhere. The surface not heat when it is charging.Inside the circuit board all use the highest quality electronic accessories,built-in safeguards protect your devices against excessive current,overheating.Apply to I i phone, Samsung Phones and other Android phones. Device is designed for charging only. Not data transfer enabled.