Portable Rechargeable Heating pack is designed to be a warmer for hands, feet, neck, shoulders, back aches, cramps, sore muscles, arthritis and many more uses.The heating pack is soft and comfortable, it is made with high grade velvet fabric on the outer shell and double thick and flexible PVC sheets inside.The hot water bottle will be filled with water by yourself only, it is non-toxins and chemicals added, you just need to charge to heat the bottle, and you have no need to change water every time like the rubber bottleWith built in automatic safety shut off function, the power will be shut off when water is at 167 degrees, also the LED indicators will show you whether the bag is heating or not, so it& 39;s safe enough to us.Rechargeable Electric Hot Water Bottle Heat lasts 2 - 5 Hours - Portable Heated Pad Pain Relief