Tube Pro Inc manufactures the highest quality snow tubes, river tubes, water park tubes and towable boat tubes for snow tubing resorts, canoe livery outfitters, amusement parks and recreational boaters all over the world. Tube Pro tubes are really the cream of the crop. Extra heavy duty 30 gauge blue PVC vinyl. These are the Cadillac of river tubes. Designed for a single rider. 2 air chambers; Safety chamber and main chamber with Boston valve. 2 large support handles. 1 beverage cup holder. 16"" (40 cm) inner diameter hole.