The Improved Fresnel Lens Optical Landing System (IFLOLS) is an optical landing aid used aboard Naval Air Stations. It is designed to give glide path information to pilots to help them land. The trailer is a TIG-welded, specialty manufactured variance of the MHU-141/M munitions trailer. It is used primarily by the Navy and Marines Corps.
PDI manufactures two versions of this trailer - the "-WC" which includes a center support channel, and the "-NC" which does not include a support channel.