Speed Sac Sprint Trainer…Outrun The Competition! Is your lack of speed preventing you from becoming a gamebreaker If so, this training aid can help. Its use of variable weight strengthens your lower half, which enables you to explode from a set position. On the court, on the field. It doesn’t matter. For once, you’ll be ahead of the pack! SKLZ Speed Sac Sprint Trainer features: Quickly improve your 40-yard dash time and overall speed and explosiveness Safely strengthen lower-body muscle groups with multiple weight options Includes 3 durable weight bags that can be filled with up to 10 lbs of sand (30 lbs total) Won’t harm grass or mar wood floor Adjustable leash length to accommodate athletes of any size Variable Weight Sprint Trainer…Improve Your Speed!