Power Pack rcB 1800 for Lenz Battery Heated Socks. These rechargeable packs extend the run time for your Lenz socks and compatible with virtually every generation of Lenz products. light lithium packs fit all models of Lenz heat socks, heat vest 1.0 and heat bandage 1.0 attach battery to legband of the sock via press studs heat can be regulated via 3 settings on the battery pack heat can be continuously regulated remotely via smartphone (Bluetooth 4.0) heat can be regulated remotely via 3 settings (accessories) heat development for up to 20 hours global charger with charging display short charging time flexible plastic case Package content 2 lithium packs rcB 1800 (rechargeable) 1 USB-charger 100-240 V with charging display Battery technology Rechargeable lithiumion batteries, rechargeable Temperature control Heat can be regulated via 3 settings on the battery pack, remotely via smartphone (Bluetooth 4.0) or remotely via 3 settings (accessories) Temperature Levels | Heating period Level 1: 42 °C / 107 °F, 10 – 14 hLevel 2: 52 °C / 125 °F, 5,5 – 7,5 hLevel 3: 60 °C / 140 °F, 3,5 – 4,5 h Choose your temperature smoothly trough the new Lenz heat app.