Do you sell unpowered non-electric amethyst mats, do they have benefits?
Any amethyst mat can be used in unpowered mode. It is still beneficial as the mat can use your own body heat to generate crystal FIR rays or negative ions. It also cools you in summer.
The mat can be recharged in the sun in the summertime. It may be preheated even more than the standard electric mat. You can also preheat it with a cheap electric blanket and sleep on the warm mat. The stones will hold warmth until you get asleep.
The best of all is that it can be used for active exercising, which can damage the heating mats.
Many customers choose unpowered mats for pets (the cats adore such mats).