Ideal for travel. 2-in-1 external mobile power and handy warmer. Push the mini-USB plug of dedicated charging line into warmer's Mini-USB socket. Make sure they are closed. Connect the USB plug of dedicated charging line with standard USB equipment, such as PC, notebook and so on. When charging is going,key doesn't work,heat function stops working. (even it is working before charging). As an external battery, it can charge for: PSP, NDSI, Sony-Ericsson phone, Nokia phone, Sharp phone, iPod nano, iPhone 3G, iPod touch, Dopod phone. Heat temperature range: 0 -40 degree C. Use temperature range: -10 - 40 degree C. Batteries inside: Li-batteries,3.7V, 2600mAh. Charging time: about 5 hours (with standard USB equipment). Heating time: 7-10 hours. At the first time of using or after longtime unused,please charge it before using. Li-batteries inside are rechargeable. The capacities will still up to 80% of standard capacities after 500 times charge. Input: 5V 1A Output: 5V 1A