Super amazing item! This thing could outlast many lifetimes :). Tested in water to confirm no leakage. Unfortunately the cap holding the air in did not survive. I attempted using a regular tire cap, but it did not seal tight enough, thus I thought I put it up for sale hoping someone could come up with another solution. Surely there are other caps to fit this particular threading. As in the title, this is made from hot vulcanized rubber. The red and blue material on the front and back is a tight woven canvas. Here are some surface cracks on the yellow as seen in the photos. Item is being sold as is. EXTREMELY RARE ITEM!

Thanks for looking :).