Wikipedia
Phiten is a Japanese company producing apparel, athletic tape, supports and braces, lotions and gels, necklaces and bracelets, health food, and other wellness-related products. Phiten also produces hair-care products under its beauty division, Yuko. All Phiten products are incorporated with one or more "Aqua Metals". The name "Phi-Ten" is derived from the Greek letter "Phi" Φ, and the exponent 10. The "Phi" Φ is used as a symbol to represent the golden ratio in the natural world while "Ten" (10) used as an exponentiation base signifies the infinite possibilities at both the micro and macro level.
Some Major League Baseball players wear the company's nylon-coated necklaces, although it is not known whether it is for the perceived physiological benefits, because of superstition, or a combination of both. However, there is no medical or scientific evidence supporting any physiological effect of Phiten’s products, and for many they are seen as mere superstition and ritual. In 2016 instructors at the United States Air Force Academy conducted a double-blind controlled test of the Phiten titanium necklace and found that there was no significant difference between a piece of clothesline and the Phiten necklace.