The OL 700-4pi integrating sphere from Optronic Laboratories Inc. is designed for total and partial luminous flux measurements of LEDs and on-site calibration. An internal reflectance/auxiliary lamp calibrates the sphere and compensates for changes in the spectral efficiency caused by the self-absorption and reflectance properties of the LEDs and their packages. For use with the OL 770-LED test and measurement system, the 9.75-in. high-reflectance integrating sphere has a 90° entrance port to exit port configuration, standard viewing angle positions of 40°, 60°, 90° and 120°, and >99% spectral reflectance properties in the 300- to 1700-nm range. An attached enclosure can accommodate a number of standard and customizable holders, and the system has a retracting cover for easy LED installation. The holder is mounted on a manually controlled, belt-driven rail assembly for positioning under various measurement conditions.