EUC back up set of Whoop gear! Whoop requires paid membership for use. There is a free device and battery charging pack offered with membership--this device and battery set are in case your original device and charger gets lost or broken. This is actually a backup device I purchased new for $75. Battery pack charges with USB-C cable and then snaps onto device. ** Recommended for people who already have a WHOOP membership! Do not buy without checking requirements for use in WHOOP website. Includes 3 straps: two black straps and one stone strap. apple watch, train smart, crossfit, sports training, peak performance, gym rat, athletic wear, competition, workout gear, biometric recovery