I bought a Phiten FATO X45 titanium collar (brand worn by Liu Xiang). I don't know if it's psychological or really effective. I used to have a sore neck and dizzy brain after playing mahjong all afternoon, but I haven't had the above problems since I put it on. However, whether it is psychological or really effective, as long as the neck is not sore, it is already a success of the titanium collar.
Efficacy: It helps to strengthen blood circulation in the body, relax nerves, relax neck and shoulders, and relieve body and mind. Increase the transmission of human energy, improve physical strength, improve endurance and concentration.