You can put all sorts of stuff at the bottom of your bowl to achieve similar results of Nording stones.I’ve thought about trying keystones for my pipes that are not filtered, but just haven’t pulled the trigger. Is Nørding the only one who makes them?
I have tried Denicool crystals, but I don't like the taste when they scorch.
I cannot find a retailer for meer chips.
I have some success using charcoal pieces, also coffee beans.
Some recommend rice.
If one is willing to experiment, try different types of aquarium gravels and potting soil amendments.
For me, the chief advantage is a better burn and draw, cuz of the air space beneath the tobacco.
So I use Nording stones on filtered pipes to compensate for the slightly restriced draw -- some folks pack looser when smoking with filters, but with Nording stones I find I can pack real tight with no problems.
Other advantages are: filtering, moisture absorption, protection of bowl bottom, and less wasted tobacco.
Again, for me, the chief advantage is a good burn and draw. Also, I can smoke to ash without fear of burning/cracking the bottom of the bowl.