The 819D-IS-5.3 Integrating Sphere is our new 5.3 inch, PTFE based, 4-port integrating sphere. Its damage threshold is 5.0 J/cm2. The diameter of the 0° port is 2.5 inch, but the sphere comes with a 2.5 inch to 1 inch port frame reducer 819M-PFR-1.0-2.5 pre-mounted. The 180° port comes with a 1 inch port plug pre-mounted, to simulate 819D-SL-5.3, but the port plug can be removed and mounted on any other 1 inch port in the sphere. The port at the North Pole location (top) can be used for fiber optic taping to monitor wavelength.  Your measurements will be insensitive to errors caused by detector positioning or problems associated with overfilling, or saturation, of the active area of the detector. All spheres include a baffle between the 0° and 90° ports, which prevents direct illumination from the light source to the detector port.