There is a set of 3 LED bulbs to indicate the heat setting - one LED light on means it is in level 1, heating from two sides and keeping temperature at 45 ℃;two LED lights on means it is in level 2, heating from two sides and keeping temperature at 50℃; three LED lights on means it is in level 3, heating from mirror-polished side and keeping temperature at 55℃.
Featuring various protections, including overheating, overcharging, overcurrenting, it is safe to use.
It can supply electricity for you mobile phone in emergency, while it will not heat up to keep you warm for charging phone will genetrate heat indeed.
With silicone loop on it, you can wear it around you finger for secure grip and easy movement.