SKLZ SpeedSac Pro Variable Weight Sprint Trainer

Seems sturdy and very well made. Everything about it looks like it'll last for quite a while. It's perfect for travelling athletes as you can empty out the sand and refill it, so no heavy items to check in.The one problem is the belt. The belt is sturdy, but too big to fit me snugly. I have a 32inch waist and the loop is under the strap when pulled tight, the velcro keeps it attached, but there's a gap and doesn't sit as snugly as you'd want. Skinny kids might have a bit more of a problem.

This is a heavy duty piece of equipment. The quality is clear, we use it on a regular basis and have been pleased.

doesn’t follow any weights

I LOVED IT