the concept a tube within a tube. the inner tube is filled with a safe sodium acetate solution and then hermetically sealed. the outer tube is filled with the formula. once the seal has been broken the tube starts warming. the selfheating tube is suitable for facial formulas like masks, body oil and eye antiwrinkle treatments. it adds an extra soothing experience to your formulahttpwww.cossma.comennewssingleviewartikelcosmogendesignsselfheatingtube.html