GRITGRIP - 2 Chalk Block Cartridges - 100% Pure Magnesium Carbonate. for Better Grip in Weightlifting, Bars, Gymnastics, Rock Climbing, Gym.Two Pack of Magnesium Carbonate Chalk Block Cartridges that are meant to be inserted into GritGrips Magnetic Chalk Bag and broken down with hands into a fine powder that will increase your grip while doing acti..