CHALK UP FOR THE SENDBlock chalk is the stuff that sweaty climbers know and live. No frills, no hyperbole, just compressed magnesium carbonate. Our favorite is by Metolius-great texture and a special drying agent give it the edge. 2-ounces in a re-sealable, zippered plastic bag. #1-selling brand of climbing chalk in America. Original chalk specifically formulated for rock climbing. Highest-quality magnesium carbonate. Safe drying agent added for maximum sweat absorption and friction.