I'm going to start this off by saying you probably won't be able to find them.

So I was lucky enough to be able to actually track down 2 packs of concentrate stones. These used to be used for smoking dabs but they got phased out by bangs and other glass pieces.

To use them in a normal pipe bowl you actually have to break them into smaller pieces. After you do that I recommend placing one screen in the bottom and then adding the pieces of stone on top.

They add no taste at all and don't have to be replaced. The only maintenance is dumping it out torching it until it's grey again and refilling the bowl.

You can be skeptical all you want but until you try them you can't tell me they don't work. It has completely changed how I use pipes and bongs.