There is a Groupon for an emergency phone which retains power for 15 years right now.
It is 68% off, just sending an FYI since it is such a smart investment. I am going to get one for each of me and DH's cars, one for our house and one for the boat. Everyone with kids needs to be able to reach emergency 911 if needed so I thought this was a good buy.
Just fyi'ing so all the moms have a chance at it.