... 2011 New style Electric hand warmer With rechargeable polymer battery inside Super great to warm hand in cool winter Reusable 2011 New style ... for about 3 to 4.5 hours to warm.with a polymer battery(3.7,1800mA) inside that ... danger of the batteryBig space for customer to print logo ,OEM is welcome.Input power:5V,500mASpecification :Item ... ':105,408pcs 40'HC:122,400pcs 2011 New style Electric hand warmer