Large ballistic nylon outer bag with one matching ballistic nylon filler bag to hold up to 150 pounds ( 68 kg ) of sand. This is a great bag for doing low to medium rep strength training with overhead moves. It can also be used with less sand to do more moves than when fully filled. And, by purchasing an extra large filler bag, the sand load can be cut in half to make it hold either 75 or 150 pounds for plenty of power and strength training moves! We designed our bags to maximize the shifting sand effect. Putting the sand in one bag that is the same length and width of the outer bag allows the sand to move together with the outer bag, giving the best sandbag training effect. Workout Sandbags are the right training sandbags for you!