There is nothing different between these and the ones that came with your fire starter. They'll work just as the originals did. They burn for about a minute when used properly, and will give you more than enough time to start a proper fire.
Keep in mind, you can use these without the actual Zippo fire starter. Any flint will do you well with these. The only reason you'd need the Zippo unit is for waterproofing these tinder sticks.