Firstly we can know the specifications of feet warmer
Size: 250x75mm or 230x70mm
Weight : 72g
Heating Last: 6hours,
Average Temp: 38C
Max Temp: 45C
Secondly, we can talk about its natural material, which includes Iron Powder, Water, Vermiculite, Activated Carbon and Salt.etc
Thirdly, you should pay attention to following cautions
· Must apply the warmer pad onto the outside of your underclothes never use it directly on your skin !
· The warmer pad can achieve 58 degrees centigrade, and it can continually give out heat for 10 to 12 hours, so do not use it when you sleep in night.
· Kept the warmer pad in safe situation, do not damage the vacuum packing.that will lead to the inside material leak.
Above all,you should properly store it, you should keep it dry, put it cold place and avoid direct sunlight.