Not one, but two balls of chalk!
 
The chalk ball, more economical
The chalk ball replaces the loose powder that you put in your chalk bag. A more manageable and economical format since it delivers the right amount of product and avoids spilling too much on holds or mats.
 
A more economical format
The ball format also limits the amount of airborne chalk. In the gym in particular, this avoids inhaling it and protects your health.