Standard Size of Titanium Tubes:

• 19.05 mm OD x /0.7/0.9/ 1.2/ mm WT Titanium tube
• 25.4 mm OD x 0.7/0.9/1.2/1.6 mm WT  titanium tube
• 31.75 mmOD x 0.9/1.2/1.6 mm WT     titanium tube
• 38.1 mmOD x 1.2/1.6/2 mmWT           titanium tube 

        The type and size of coil you'll need is dictated by several factors including the size of your tank, starting and operating temperature, supply temperature of heating/cooling medium, required heat-up time. Some external factors include surface ventilation, tank solution agitation, tank wall insulation and work load.