Q. On question 2907 regarding wearing electric battery heated socks on Shabbos you wrote that Horav Shlomo Miller’s Shlit’a opinion is to permit their use only on need or when health issues are involved. There is a different type of heated socks in the market that are not electric and have no batteries. They are called Tourmaline socks that are self heating. Are those permitted to use in Shabbos?
A. An online search provided the following information; “Tourmaline absorbs body heat and converts and then re-radiates that energy into the form of far infrared energy back into the body. Those far infrared photons of light are picked up by chormophore molecules in our cells. Those choromphore molecules transfer that energy to the mitochondria.
The process of converting body heat into far infrared is called energy thermal-photonic conversion.  Patients often experience a feeling that Tourma®Tape is giving off heat and feels warm to them.”
It would seem from the above description, that no real electrical current is used on these socks. Therefore, Horav Shlomo Miller’s Shlit’a opinion is that this type of socks can be permitted.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a