* Build My LED uses average spectroradiometric data for each LED type to estimate fixture performance. Actual photometric results may vary. Actual production LEDs will vary both in spectral content and radiometric flux within the LED manufacturer’s bin tolerance. If actual performance measurements are required, Build My LED offers a Custom Lighting Report for each fixture we build. The Custom Lighting Report can be selected from the option list after an LED fixture is added to the cart. These are fixture-level performance details, which include optical, thermal and electrical losses. These are representative of the results associated with an LM-79-08 report, which is the official IES test protocol for measuring light output of solid-state lighting products. Some companies only list the performance specifications of the LED, but this is not an accurate method of assessing the radiometric performance of a finished lighting system.