Meet the Kingii: an inflatable wearable that you can put on your wrist to get out of trouble in the water. The device can be inflated quickly when you need some help. It has a compass and whistle as well. The CO2 cartridge is replaceable, so you can use your Kingii as many times as you like.
The above video shows Kingii in action. You can find out more on Indiegogo.