I know this isn't the typical gear but...so I had seen this device in a Duluth Trading catalog but I wasn't paying $30 for it. It is a magnetic Red LED flasher that you can use like a road flare but last a heck of a lot longer. Up to 100 hours low flash. I got mine at Menards for ~$10, even at this price I think its a bit high but better than $30. It does seem to be well made, it says its crush resistant, it has a rubber seal to prevent water from shorting it out. It has an eyelet to tie it down with cordage. The rubber edging allows for it to be magnetic but not scratch paint. It has 9 light modes ranging in duration from 10 - 100 hours. It uses a CR123A battery. Claims to have a 10 mile visibility on clear night from the sky.

Might be worth putting in your car kit. I may try to do a video on this.