The Tire Ring Base is made from recycled truck tire sidewall sections. This 25 lb base is economical and easy to use and provides all the ballast you'll need to hold a drum in place. Simply drop one or two 22.5 inch diameter tire rings over the drum top and you are ready to go. Each drum has a unique retaining lip that acts like a flange to hold a tire ring securely in place. The rubber tire ring grips the road and minimizes drum movement and rotation. Designed to stay together when dragged or moved around construction sites.