Dimensionally stable and dustproof chalk bags.
Saka by Petzl is a classic chalk bag that does not allow magnesium to escape. The edges are reinforced so that the chalk bag retains its shape. The drawstring closure keeps it tight and can be opened with just one hand. The lining is sewn into the bottom so that it stays on the ground even when you're searching for the last chalk crumbs. And if you have two favorite toothbrushes for cleaning, you can take both with you in the Saka.