A Q-Ray bracelet is an expensive piece of jewelry worn by people who wish to show off their gullibility. Woo-hoo, let's hear some applause for people who don't think. The bracelet allegedly acts to relieve pain through some sort of process explainable by the best pseudo-scientific gobbledygook or by the Placebo effect.
One "explanation" for the apparent relief of pain is that prolonged contact with the skin produces copper oxide, which is known to damage the central nervous system. Wearing the bracelet around the wrist would damage the median nerve and thereby reduce the sensation of pain in the hand, so if you feel like damaging your nerves you know what to do.
A Q-Ray was reportedly once used by Doctor Doom.