Capacity: 2200MAh / 3000MAh(Spare battery). Not necessary. The current battery technology is mature, and battery life will not be affected. There is indeed only one sock, because this sock is mainly used to wrap the battery, protect the battery, and prevent collisions.
SAVIOR HEAT Spare Battery Rechargeable for Heated Products 7.4V
8.4V 1.3A SunWill Power Charger for Heated Jacket/Gloves - DayWolf
Rechargeable 7.4V 2200mAh Lithium Polymer Batteries
Savior 7.4V Men's Waterproof Battery Heated Jackets – Savior Heat
Spare Batteries Motorcycle Heated Gloves
SAVIOR HEAT Heated Gloves for Men Women, Electric Battery
Dual Battery Charger for Heated Gloves Socks Hat - SAVIOR Heat
Spare Rechargeable 7.4V Li-ion Batteries - DayWolf Sports – Day Wolf
Extra Battery for Heated Jacket Gloves Socks - SAVIOR Heat
Savior 7.4V Thick Battery Heated Leather Gloves Five fingers