Made of durable silicone and polycarbonate plastic, it is resistant to sweat and water, making it great for use at the beach or swimming pool. Installation is easy. Simply remove the old watch band from your Fitbit fitness tracker, then install this green watch band replacement. Designed to fit smaller wrists, it can be adjusted to fit wrists ranging from 5.5 to 7.1 inches in circumference. To measure your wrist size, wrap a piece of string around it, then measure the string from the end to the point where it crosses over the end using a ruler or tape measure. These fitness tracker replacement bands are green with a black buckle. Please note that the Fitbit fitness trackers pictured in the images are NOT INCLUDED.