The Fitbit One clip accessory is made of silicone and metal.
Fitbit One is sweat, rain and splash proof. However, the device is not swim proof. With any clip-based wearable device, it’s best for your skin if the clip stays dry and clean.
You can clip Fitbit One to a belt, pocket or bra. Always use the silicone holder when clipping it to a bra or waistband as the plastic Fitbit One tracker is not meant to be worn in direct contact with the skin. Make sure the Fitbit One display faces outward when clipped to your bra. Learn more.