More features than dumbbells, kettlebells and barbells combined! FREE DRAG STRAP! ONLY 2 REMAINING! Instead of filling up standard sized sand bags with limited functions, we designed the Slam Bag to comprise of 4 mini sand bags for the internal weight. Simply remove the sand fillers to increase or decrease the weight. Additionally, the bottom of the Sand Training Bag is reinforced with two military grade adjustable flaps to tighten or loosen the size. The Sand Training Bag comprises of 24 x-box Nylon stitched with an additional 2 rivets on each handle. The 3 loops on each side comprises of a total of 6 x-box Nylon stitched with an additional rivet to prevent twisting and raising during use. On the interior, built-in reinforcement sand filler straps to lock in any added sand filler, creating a stabilizing structure when cinched down. *Sand is not included