REI matches are longer than regular strike anywhere matches and won't fit in traditional match safes.
The REI matches are not MUCH longer. I took a pair of scissors and trimmed the woodend end just a little to allow it to fit one of those cheap orange Coghlan's match safes. Works like a charm. I can fit about 10-12 in there.
Also, the REI matches are fattest at their heads, so there is a lot of extra space around the "handle end". And often times, a simple kitchen match would be enough. So I have the REI matches stored heads-up in the safe (which is slightly tapered), and I took some kitchen matches and trimmed them a little bit. Now, I have those stored head-down with the REI matches, and I can get about a dozen of those in there, occupying unused space.
So, now I have two striker strips, one dozen REI, and one dozen kitchen matches in one safe. Not too bad.
Oh, and I did check, and the safe is waterproof for 30 minutes completely submerged in a glass of water.