Gently used Higher Dose PEMF Infrared mat, about 1 year old. Works well. From the company website:
The Infrared PEMF Mat combines two powerful healing technologies to create the ultimate recovery tool. PEMF grounds you in earth’s magnetic field for a full-body reset, while Infrared’s deeply penetrating heat doubles your DOSE. Hit the mat to ease chronic pain, recover from workouts, deepen your meditations, or experience total-body relaxation. No set-up or clean-up required.

How does it work? Pulsed Electromagnetic Field (PEMF) therapy emits electromagnetic waves that mimic natural frequencies found in nature, stimulating and encouraging your body’s natural recovery process. The benefits of PEMF alone are out-of-this-world (literally, astronauts used it to recover from a debilitating space mission), but even more powerful when paired with infrared’s deeply penetrating heat and twenty pounds of healing crystals layered inside the mat, which produce negative ions (think: antioxidants in the air) when heated.