The 81311 Air Mass Filter corrects the output of a xenon lamp to better match the solar spectrum found outside of earths atmosphere. This 2 inch x 2 inch filter fits into a solar simulators integral filter holder, with a convenient pull handle allowing quick and easy insertion as well as removal of the filter. It can be mounted in most solar simulator models. The 81311 is an AM 0 type filter to the ASTM E 490 standard.