The Chalk Ball contains approx 50gr of 100% top quality magnesium carbonate. Lyon Chalk Ball. A standard sized chalk ball for use in all but the smallest of chalk bags. The chalk is keep neat and tidy inside a fine mesh bag to stop it spilling all over the floor when you fall off! Most indoor climbing walls now insist on balls instead of loose chalk, it keeps the dust down and stops chalk getting all over floor. The fine mesh bag delivers just enough chalk to your fingers so there is less waste.