The AIRE Rocktagon River Tube has been discontinued by AIRE. It was an uncoated fabric version of the RocktaBomb tube, which is AIRE's lone model now. What kind of rivers can you run in a tube? Many buyers will only float gentle streams, though for the more adventurous, what you can get away with depends on your ability to read moving water & rapids. With a proper lifevest and experience, intermediate rivers are possible. Brushy streams with strainer hazards, however, should be avoided at all cost when you don't have paddle control. Great for wavy, open low flow waterways or deeper slower moving water. Always wear a life jacket and helmet. The current RocktaBomb version utilizes an urethane bladder, like all of AIRE's U.S.-made boats. The NRS brand tubes use a less durable vinyl bladder.
As kids we'd go to the local service station and pick out discarded truck inner tubes and patch them. We called it "inner tubing" and ran rivers and creeks in the Smokey Mountains, Michigan, Illinois, Wisconsin, and California. A river tube surely has it's place for any river runner. (not every day is a serious rodeo competition).
ps. Radial tires have probably stamped out the former glut of free inner tubes at EVERY service station across America and the world. Poor kids now-a-days, what are they going to do? Play video games on their cell phones?