[–] NoTrueScotsman [S] 0 points 0 points (+0|-0) ago 

These are sort of a legend on piping forums. They're synthetic, but handmade and customized to the purchaser's particular pipes. The guy making them has only done so off and on, since it's not his full time job.

I hear they're quite powerful in the make of pipes I have, which already have a pretty full bass drone.