Platysens Marlin is a Swim Meter designed to tell you your swim performance through voice feedback using a bone conduction headset. Your pace is reported to you as you swim with no disruption to your swim stroke. In open water swims, your swim performance is captured with GPS. In the pool, motion sensors are used when there is no GPS reception. After your swim, you can connect Marlin to your phone with Bluetooth to review your data and update configurations.