Compatible: Specially designed for Fitbit Charge 4/Fitbit Charge 3 and Charge 3 Special Edition, replacement strap is a good companion for Fitbit Charge 4/Fitbit Charge 3 activity tracker. Special Note: tracker is not included Available in two sizes : Samll size for 5.5"- 7.1"wrist; Large size for 7.1"- 8.7"wrist. The strap can also be adjusted according to the size of your wrist. Multi-color Choices: 12 colours are available for Fitbit Charge 4/Fitbit Charge 3 wrist straps to give you a variety of choices to highlight your personal style Material: Made of Soft TPU and with two sturdy snaps at the ends of the strap to securely hold the Charge 4/Charge 3. Comfortable to wear, suitable for many scenes Easy to Install : Fitbit charge 3/charge 4 strap only need 3 seconds to install. The Pin closure will lock your fitbit charge 3/charge 4 interface precisely and securely, avoid falling off.