What You Get: 3 * slim replacement band for Fitbit charge 3 & Fitbit charge 4 & Fitbit charge 3 se (Fitness Tracker is NOT included) How to choose your size Wrap the rope around your wrist and make a mark at the wrist comfortable position, Use a rule to measure the length of the rope from zero scale to the marked position, Small is for 5.5" - 7.1" (14-18cm)wrist, Large is for 7.1" -8.7"(18-22cm) wrist. Tips: choose the same size as the original one. What occasion fit It suit for sports, business, casual, etc It can also be given as an adorable gift for your lover, kids, family and friends during wedding, party, holiday, birthday, anniversary, Mother's Day, Thanksgiving Day, Christmas, New year, etc How to install and remove straps Just press the metal piece which is under the connectors in two ends and connect the strap onto the charge 3/4 Hear a click as the strap clip into the right place Press down the metal piece Pull out the band Tips: Twist the band to ensure the clasp snap up when it is locked onto the wristband. How to maintain your bands Please keep your bands clean after exercising or sweating. Avoid contact with dark clothes directly to avoid discoloration of the strap. To prevent yellowing, please avoid strong sun exposure, rain or high temperature.