The peanut lighter normally uses all the same parts as a Zippo and works on the same principle. It's just a smaller version. It has an advantage over the Zippo though in that the cap screws on with an O-ring so the fluid doesn't evaporate nearly as quickly as a Zippo, even if the Zippo has a ranger band. With a Zippo and ranger band I can usually get 3+ weeks of use before having to refill. With a peanut lighter I've gone more than 6 months before needing to refill. That is a substantial difference!
Many types of peanut lighters on the market. A common one is this;
They work. However, I've noticed that after a while the seal breaks. In the video you'll notice that the top pulls out of the body for refill. The top part with the striker and flint tends to pull apart from the canister that contains the filler. I guess the fluid eats away at the seam? It can still be usable but gets pretty flimsy. I still have several of these and they do last as far as fluid evaporation but all of them eventually split apart at that seam. Perhaps a more expensive version wouldn't split apart. However, the inexpensive ones are so inexpensive that you could buy a handful and if you had to replace it annually it really isn't a big deal.
I prefer the type in the pic below. The striker part is in the bullet part of the lighter. It unscrews just like the other type to allow access to the actual lighter part. Seals with an O-ring to keep it water/weather proof. In the base, where the key ring is attached, it also unscrews to get to the fluffy filler and is where you fill/refill with fluid. So there is no pulling out inserts to put stress on seams. The base also has an O-ring to keep it all sealed up.
