SKLZ Unisex's SpeedSac Variable Weight Resistance Training Sled (10-30 Pounds), Black/Yellow, One Size

Variable weight resistance trainer helps sprinters, football players, and other athletes strengthen lower-body to improve speed and explosiveness
Three removable weight bags can each be filled with up to 10-pounds of sand to adjust towing resistance for variable weight training
360-Degree belt ring allows for multi-directional training to improve strength and mobility in any direction; adjustable leash fits any sized athlete
Durable nylon shell for use on grass, turf, or wood surfaces; Velcro-secured straps hold weight bags firmly in place
Includes speed sac shell, 3 Sand bags (sand not included), Adjustable leash and waist belt; limited 1-Year manufacturer’s