For the Inspire, Inspire HR, and Ace 2, Fits Wrists from 7.1 to 8.7", Flexible and Durable Elastomer Material, Aluminum Buckle Closure. Whether you wear it to work or while working out the Fitbit Classic Band for Inspire & Inspire HR Fitness Trackers is a stylish option for your Inspire Inspire HR or Ace 2 fitness tracker. Constructed from a flexible and durable elastomer material it can handle everything from sweat and rain to a dip in the pool. When attached to your fitness tracker the band can be secured to your wrist via an aluminum buckle.