Features light lithium packs fit all models of lenz heat socks, heat vest, heat bandage + LED system attach lithium pack to legband of the sock via press studs heat can be regulated via 3 settings on the lithium pack heat can be continuously regulated remotely via smartphone (smart ready) h eat development for up to 20 hours global USB-charger with charging display and short charging time short charging time flexible plastic case Package content 2 lithium pack rcB 1800 (rechargeable) 1 global USB-charger 100-240 VAC 1 USB charging cable with charging indicator