Weight Sled Trainer Adjustable Power Sled SandBag with Belt for Sprinters Fitness Weights Workout Sports Equipment                1.These bags DO NOT come with sand/pre-weighted. But they can be filled and then added to the sled, and then strapped into place with Buckle. These bags will stay secure during your workout. The leash and waist belt are also adjustable for your comfort      2.Pull the attached weight in any direction, whether sprinting forward, backpedaling, or shuffling from side to side.     3.Useful for Athletes - This is a great training tool for anyone in sports where speed needs to be improved. You can use it to increase the overall speed and agility of athletes. The adjustable training sled is helpful for Athlete's speed and leg muscles.     4.Unique design - The materials in the bag are hefty, and well made. This is a bag you drag on the ground. It comes with 4 bags, The more weight you drag, the more you work and the stronger your legs become.          Material:PVC mesh cloth     colour:black          Package Contents:      1 x Waist belt     1 x Shell bag     3 x Weight bag     1 x Strap          Only the above package content, other products are not included.     Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.