Wrist – Bottle Neck Seal
The standard weight are available in 4 sizes where as the heavy duty are only available in Med and large. Bottle wrists give a greater contact area to the skin against the cone version so are good for faster impacts into water such as water-skiing, wakeboarding etc. They are also better at sealing against the skin if you have tendons that protrude away from your wrist.
Below is the guide on sizing.