The wristband is made of liquid silicone rubber.
The lenses of the wristband should be cleaned periodically. a simple wipe with a damp cloth is sufficient to clean both devices. Do not use alcohol, harsh chemicals, or solvents on the device.
The Wristband is fully waterproof and can be left on while you bathe or shower. It is, however, recommended to remove the wristband periodically so your skin can have a break.