For better traction on mud, snow, and ice, the LLV interlocking jig-saw weights are the innovative, practical, and sensible solution for adding weight to prevent skidding. This complete jig-saw weight set adds substantial, well distributed weight to the back of postal vehicles.The jig-saw pieces can be easily arranged and are textured to resist sliding. If you find yourself on a particularly icy patch, pop a plug and pour sand on the ice for added traction! This complete set contains a total of 20 pieces -- 10 side pieces, 4 corner pieces and 6 inside pieces made of durable, hollow polythylene casings that can easily be filled with sand, sold separately. Each piece weighs 18 lbs. when filled. Ships USPS.