Inner tubes are a type of rubber tube that is used in a variety of applications. They are commonly used in the automotive industry for tires, but they can also be used in medical and industrial applications. The two crossword solutions for the term 'inner tubes' are AORTAS (6 letters) and BRONCHI (7 letters). Aortas are the main artery of the human body, while bronchi are the airways that connect the lungs to the trachea.