Capillary tubing is generally defined as tubing 0.125” OD and smaller. Tubing Central stocks a wide array of tubing in 0.125” OD, 3mm OD, 0.063” OD, and even smaller dimensions. Tubing is available in stick and coil form and a variety of tempers, including fully annealed, half hard, and fully hard. This tubing is used in various applications including chromatography and medical equipment.