The MOA III, designed and manufactured in the United States of America, meets the rigid performance and environmental requirements of U.S. Department of Defense (DOD) military specification MIL-S-83129A. It also fully complies with T.O. 33-1-37-3, TM 38-301-3 and NAVAIR 17-15-50.3 monitoring programs. Composed of three distinct modules mounted on a single frame, this compact design incorporates temperature compensating construction and comprehensive shock mounting. In addition, the polychromator features pre-aligned exit slits for all elements-of-interest so as to facilitate field upgrades as analytical requirements change.