... Safety Standard about Lithium-ion Hand Warmer, 100% safe *•Pocket designed,convinient for travel* •Intelligent Temperature Control System, Supplying Pulsed-type ... hours continuously, and heating time changes along with external temperature *•Double-side heating, fast heating through the two stainless steel surface ... 88*83*33mm; NW:110g/GW:200g Portable USB Recgargeable Double-side heating Hand Warmer