... carbon content is as more as 90%.When USB Warm Pad is energized,the carbon material will ... the above principle,we make full use of double heating, and use the low voltage to supply ... as possible (conversion rate is about 98%). Furthermore,USB Warm Pad has good endurance ability against high ... periarthritis.3. Power supply: connect with computer through USB, low-voltage ,safe and convenient.4.Usage:lay ...