COMPATIBILITY: Personalized Your Fitbit Luxe,Inspire 2,Inspire, Inspire HR, Flex, Flex 2, Alta, Alta HR, Ace, One, Charge 5, Charge 4 ,Charge 3,Charge 2, Garmin Vivofit / 2 / 3 / 4, vivosport, vivofit JR, vivosmart HR Activity Trackers. Fitness Tracker NOT included. COMFORTABLE: The surface is made of premium neoprene material, soft and delicate, comfortable and breathable, to prevent your belt from getting wet. The internal is made of microfiber, it’s skin-friendly. PROTECTION: The ankle strap comes with a secret pocket, you can put your fitness tracker into the secret pocket that ensures your fitness tracker stays securely inside. DOUBLE CONCEALED BUTTON DESIGN: Zinc alloy double concealed button design, fits 8.2"-12.2" (210mm-310mm) ankle circumference, comfortable to wear, ensures the ankle strap is fixed to your ankle. WATERPROOF AND SWEATPROOF: The air holes on the surface make you feel comfortable and breathable, the wider and thicker design makes you feel less tense, it can waterproof and sweatproof.