It's called Project Ryptide. It's a device that you can attach to a DJI Phantom that will deliver an automatically inflating life preserver to a swimmer in trouble in just a few seconds. After a year of development and testing the product is finally available to the general public. You can find it on Kickstarter here: http://kck.st/1D5UHol The device weighs less than 400 grams and attaches to a Phantom in just a few seconds. It uses the Gimbal level to deploy. To use it, you just fly over the person who needs the life preserver and slide the gimbal lever to deploy. Here's a preview of it in action: https://youtu.be/FFllAOjRj-4 Take a look when you have a chance.