I got a pair of these today to put in the safe, thanks to some very good advice from a fellow TFL member. I wish I could remember who to give him credit for suggesting them. Built-in plug and only draws 22 watts for 10 hrs. to "recharge." Much cheaper than running a 300 degree oven for 3 hrs. to recharge the old ones.
If you can't run a "goldenrod" in your safe, this might be the next-best thing.
If you can't run a "goldenrod" in your safe, this might be the next-best thing.