I prefer the RAF type, smaller with a better striker. They do that too. Don't bother with that Maya Dust stuff; marketing gimmick that only takes from a flame. Use cotton wool instead it's cheaper and quicker. Rub vaseline or lipbalm into and it burns twice as long, almost a mini candle.
First link is the full NATO fire kit, if you just want the striker that would be more cash than you need to pay. The striker from the RAF kit is my preference that site calls it the 'Ranger'. The second link is the b'stard offspring of the Swedish flint (as used by Lars Felt, all round top bloke and Arctic Survival Guru) and the RAF one. Good saw striker with chunkier flint rod, haven't used one but can't see any reason not too.
All of them work just depends which one lights your fire...
Unlike lighters and matches, a sparker can be packed into hand or hold baggage for flights and will not leak or expire over the years if it is not used (they are intended as emergency use items rather than day to day use for setting fire to things like the end of fags). Sparks from a lighter are nowhere near like these purpose made fire-steels, they are composite rods which produce large sparks at thousands of degrees heat required for ignition. In full Arctic conditions the tinder used to catch the spark must also be warm and dry, it really is a fine art and I would not fancy my chances in a real survival situation relying on this kit. I'd need a decent doss-bag and a bottle of rum.
That said, I would suggest that in a military 'survival' scenario you should have bigger issues to worry about than lighting fires and I would suggest that reliable comms and 'other items' will be of greater use than any fire-sparker could be.
For those who may require one for any reason, may I recommend the following links: