CRAIN 517 5' ALUM STRETCHER TUBEAluminum stretcher tubes are lightweight and rustproof. The No. 517 5' Aluminum Stretcher Tube can add up to 8 feet 8 inches of length to your stretcher in 4 inch increments enough for a variety of rooms. Crain aluminum tubes feature a score line on the inner tube and the outer tube for aligning the buttons with the holes during length adjustment. These tubes work with other standard size diameter tubes. Closed length: 5 feet. Range of useful length