Hot filling shells and stones ( pack of 36 )
The blend 2.0 filling uses a proprietary blend of vitamin-grade iron and magnesium; food-grade salt, water and absorbents. All ingredients are inert, non-toxic and biodegradable.
Once activated with water, they are ready for use after a few minutes.
They retain their heat for a period of about 90 to 110 minutes, so they are more than enough for an extensive massage.
See here how to fill the stones.