T-12 Outside Diameter: 1.750" Nominal Stocked in clear light stabilized. Stocked in clear light stabilized polycarbonate having 0% transmittance below 370 nanometers. F40 and F96 are stocked in blue, green, red, amber and pink. Sizes other than those shown above are cut to order out of the above sizes. Universal end caps are made of black high heat polypropylene and are included in each carton of tubes.