Extreme Bracelet Band – Metax is of one The EXTREME PERFORMANCE GEAR Series with METAX technology supports the performance of people who enjoy daily sports, to the athletes who compete in extreme conditions. What’s so good about this Extreme Bracelet Band is adjustable from 15-19.5cm/6-7.5″. Metax is the Phiten’s Most updated technology which is equivalent to X100 Aqua Titanium Technology! Enjoy it for yourself!!