Amazon.com: uxcell 6063 Aluminum Round Tube, 30mm OD 27mm Inner Dia 300mm Length Seamless Straight Tubing : Industrial & Scientific
K & S 1115 Round Aluminum Tube, 5/16" OD x 0.014" Wall x 36" Long, 4 Pieces, Made in The USA: Metal Industrial Wall Tubing: Amazon.com: Industrial & Scientific
Amazon.com: K & S 9317 Round Aluminum Tube, 7/16" OD x 0.035" Wall x 36" Long, 4 Pieces, Made in The USA : Industrial & Scientific