SKLZ Super Sandbag is a complete tool to add strength, stability and speed to your endurance training sessions. Execute a wide-range of training drills that will work your upper and lower body for maximum power and explosiveness. Made to handle the roughest and toughest use, the bag has a durable outer shell with convenient handgrips around the exterior, 4 weight bags that can be filled with a high-density material (maximum weight of 40 lbs.) and a strong zipper closure with Velcro reinforcement. Adjust your workouts by adding or removing the weight bags to increase or decrease intensity, the Super Sandbag is such a versatile tool, you’ll want to include it as part of your all your endurance drills and exercises.