Amazon.com: Refrigeration TubingThin Copper Tube, 1/16" OD X 1/32" ID X 9.8 FT Soft Coil Copper Tubing (1/16" OD X 1/32" ID X 9.8 FT) : Industrial & Scientific
K & S Precision Metals 1152 Round Brass Tube, 11/32" OD x 0.014" Wall x 36" Long, 4 Pieces, Made in The USA: Bike Tubes: Amazon.com: Industrial & Scientific
Amazon.com: Assorted Metal Tubes/Rods of Copper and Brass
Amazon.com: Refrigeration TubingThin Copper Tube, 1/16" OD X 1/32" ID X 9.8 FT Soft Coil Copper Tubing (1/16" OD X 1/32" ID X 9.8 FT) : Industrial & Scientific
Amazon.com: uxcell Copper Tube, 2mm 3mm 4mm 5mm 6mm 7mm OD x 0.2mm Wall Thickness 200mm Length Metal Tubing, Pack of 6 : Industrial & Scientific