I have been using them for several years now. I have lit one that was carried in my backpack (EDC) for more than 3 years, and it lit just fine. I can also start them with the Blast Match without opening them up, though not with other ferrocerrium rods. They pack small and flat, perfect for a survival kit. I have even carried them on a commercial aircraft (because I forgot it was there) with no problem, though I do not make a habit of it.