Where can I buy a far infrared therapeutic instrument in Beijing?

Far infrared rays have the functions of relieving pain, promoting blood circulation, removing blood stasis and dredging meridians. When I bought a sphygmomanometer in the rehabilitation medical equipment store opposite the east gate of Guang 'anmen, I saw a physiotherapy instrument in the store, which was on sale 128 yuan. It is small in size and convenient to use. Sometimes I feel uncomfortable with my shoulders, so I bought one. Other brands of therapeutic instruments are also available there. You can try it there.