FOODCHEM A : Thanks for consualting.It'is well konw that sodium trihydrate tech grade can be used in producing body warming products,for example,hot ice; By clicking on a metal disc in the heating pad, a nucleation centre is formed which causes the solution to crystallize into solid sodium acetate trihydrate again. The bond-forming process of crystallization is heat released.We will be honoured if you esteemed company give us the chance to provide best quality sodium acetate trihydrate products.