UTK T-Pro (31” X21”) Far Infrared Tourmaline Heating Pad with Smart Controller. Medium T-Pro. 150 wattage. PURE TOURMALINE STONES: Tourmaline emits much more negative ions when heating up (103°F-159°F/ 39.4°C-70.5°). Negative ions can improve blood circulation and relieve muscle aches. Smart controller has a Memory Function, convenient for people to set last-time temp level, 6 Temp settings and Auto-shutoff.