This Model Is an Oversized U-Shaped Neck Hot Water Bag, Dedicated for Export, with Large Water Injection and Slow Charging. It Usually Takes about 30 Minutes to Charge in Extremely Cold Winter. It Usually Takes 5-10 Minutes to Charge in Summer.
About Insulation: Electric Hot Water Bag Is Not Insulation, That Is, One Hot Water Cooling and Heat Dissipation Process Heating, If There Is Insulation, It Cannot Be Heated (Because It Does Not Heat Dissipation, Refer to Thermos Cup, Electric Water Heater).