Classic Super Chalk with eco-friendly, biodegradable packaging Metolius' classic Super Chalk, now with eco-friendly, biodegradable packaging. The #1 selling brand of climbing chalk in America! 100% Magnesium Carbonate. A safe drying agent is added to the highest-quality magnesium carbonate for maximum sweat absorption and friction Feature- 100% Magnesium carbonate No additives 4.5 oz/127g