To reduce the problems of safety, logistics, and evaluation inherent in training at night, the Army Reseacrch Institute has developed experimental light-attenuating devices (LADs) that simulate night visual conditions during the day. Single-density or bidensity lenses can be fitted to existing facemasks and used to conduct certain night training operations during the day with little reduction in effectiveness. LADs were used experimentally in training and testing night rifle marksmanship during basic Army training at Fort Jackson, S.C. Filter densities effectively approximated night illumination with a full moon, a quarter moon, and a new moon; trainees using LADs performed as well as trainees performing under actual night codnitions. (Author).