ZOX watch bands are made for Apple Watches and Android Watches. Sizing - One size fits most. The watch bands have a slider built into them to fit almost any size wrist. Compatibility: Small fits Apple watch sizes 38mm/40mm/41mm Large fits Apple watch sizes 42mm/44mm/45mm/Ultra The sizing for Android watches are a bit more confusing as there are so many different options. We have attached a size guide for you to each product page to help figure out what sizes they’ll fit. The easiest way to explain it to customers is that if they have a 20mm quick release pin, then they’ll need the Android 20mm. If they have a 22mm quick release pin, then they’ll need the 22mm connector. The sizing on these connectors is NOT the size of the face of their watch. It is the size of the connector. We also carry adapters for Fitbit Versa and Sense watches as well as Google Pixel watches. Material - The same buttery-soft and eco-friendly elastic that we produce our normal wristbands from.