This is a great set for a city apartment. They have the CrushGrind® Mini mechanisms inside, which are essentially the same as the original mechanisms but are narrower which allow them to be installed in a thinner branch.
Birch is relatively rare. Since I use only naturally fallen branches, and Birch gets soft and punky relatively quickly, most birch I find is not usable. But once in a while I'll find a freshly fallen branch and work my magic.
If you don't need a set, ask for a gift bag and tissue and gift the other when you need a stunning gift.
My Cottage Mills® are made from branches that have naturally fallen, mostly due to wind storms. As they lay on the ground, sometimes for years, the weather, sunlight, and moisture work their magic. The end result is a beautiful natural looking mill.
All have an adjustable ceramic CrushGrind® mechanism, with a 25 year guarantee.