The OL Series 455 is a high intensity integrating sphere calibration standard designed for accurately calibrating very sensitivie instrumentation. The OL 455 consists of an optics head and a separate controller. The integrating spheres are available in diameters of 4, 6, 8, 12, and 18 with exit (radiating) ports of 1, 1½, 2, 3, and 6 inches, respectively. Calibration options include luminance, color temperature, and spectral radiance.