Re-chargeable electro-magnetic warmer is produced by special plastic material. It has original creation for the conceal to avoid the children would be burn by opening the topper. It is a safe and convenience high-tech health product. Features: 1) Heal back and neck pain, It can help to treat and prevent theneck plain caused by overworked, and release the pain quickly, provide comfort for arthritic relief and relief menstruate pain, etc. 2) Take 8 to 18 minutes to heat up only, which can keep warming hand for 2 hours and warming quilt for 10 hours 3) When temperature reaches 68-75 degree celsius,it will self-adjust to the correct temperature 4) Not necessary to refill water Inner packing: color box Outer packing: carton