Therm-ic SmartPack 1600 with remote control boot heater with TrimFitTherm-ic battery boot heating systems are designed to combat sub-zero temperatures and ensures that your winter sport experience is enjoyable. The Therm-ic boot heating system is easy to use, easy to install and suitable for any boot. The Therm-ic SmartPack 1600 with Remote Control and TrimFit is designed to work in any boot or shoe and is a one-size-fits-all. The SmartPack 1600 with Remote Control is unique because it uses Lithium-ion batteries which are lighter in weight than AA or nickel metal hydride batteries. Lithium-ion batteries weigh almost half of what the other system batteries weigh and are smaller in size.Therm-ic SmartPack 1600 Battery Boot Heater with Remote Control features • The TrimFit heating elements fit every type of winter boot and is a one-size-fits-all. • The TrimFit system allows you to keep your current or custom insoles. • You can install them yourself. It took us about 60 minutes to do the initial installation in both boots. • Comfortable warmth up to 22 hours with freshly charged batteries. • 3 levels of heat that allow you to determine how much heat you want and determine how long your batteries last. • Remote Control, No need to bend over to adjust the power to your batteries. All you need to do is touch the button on the remote which can be stored in a pocket or around your neck. Both batteries adjust at the same time.Heat settings: • Low setting: 37C or 99F for 21 - 29 hours of use. • Middle setting: 45C or 113F for 9 - 13 hours of use. • High setting: 70C or 158F for 4 - 6 hours of use. • The time of use depends on the charged status of the batteries, the age of the batteries and the outdoor ambient temperature. • For longer battery time, don't leave your batteries on all day. For instance, turn your batteries off when inside for break or lunch.You'll receive: • Instruction booklet on how to use. • 2 SmartPack 1600 Lithium-ion battery packs with clips. Both batteries have integrated heat stage switches. • Battery specs- weight 3.0 ounces, size- 2" high x 2" wide x 3/4" deep. • 1 global battery charger that works in North America, UK and Europe. Offers controlled charging with charge time between 2 and 4 hours. The charger has an additional feature that prevents overcharging which allows for longer battery life. • 2 heating elements with connecting wires. • 2 TrimFit self-adhesive Cambrelle fabric covers to prevent your socks from catching the heating elements when you slide your foot in or out of your boot. • 1 remote control. All you need to do is touch the button on the remote control to adjust your heat! It can be stored in a pocket or around your neck and both batteries will adjust at the same time. • Therm-ic warranties all their products for 1 year against any manufacture defect.