I was looking at those. On most inflatable PFD I figured those would have to be folded inside the PFD in order to be visible when the thing inflates. The lights have an automatic on function, I assume to be controlled by water bridging the contacts visible on the front of the light. That has me wondering if the lights would get triggered killing the batteries inside a wet PFD with the wet fabric bridging the contacts, from rain, spray etc. Those would be great for foam PFD's or anywhere they a could be mounted on the outside of gear.