A rechargeable 7.4V lithium-ion battery to power your 7V gear - 3500 mAh of power makes it one of the most powerful heated clothing batteries around.Four power settings allow temperature control for your comfortPower Level 25% 50% 75% 100%Temperature Output (F) 105° 115° 125° 135° +Works with many other brands of 7V Battery-Powered heated clothing, including gear with a built-in button to control temperatureBattery Light Indicator will glow red instead of blue when attached to clothing that has button built-in - power level is then controller via the buttonLasts at least 3-10 hours on one charge (total time depends on the clothing item & temperature setting)Life of the battery is about 500 chargesTo check the remaining charge on the battery, press power button while not attached to heating clothing. The number of Battery light indicators lit will correspond to the charge remaining (0-100%)Warranty - 90 daysNOTE: Extreme cold and extended periods of time without use can affect battery life. Charge periodically to at least 25% to extend battery life. WARNING: Do not leave battery powered gear turned on while unattended. Battery should not be submerged in water.Shipping Note: Ships via ground transportation in USA lower 48 states only, air shipping not available due to air regulations. We are not able to ship internationally or to Canada due to shipping regulations.