Original insulation trade vintage catalog for W. J. DENNIS AND COMPANY. Main office and plant was located at 2110-2120 West Lake Street, Chicago, IL. Manufacturers of Wing Flex Window Weather Strip. For standard wood double hung windows. Can be used with various modern balances. Maintains an air seal by conforming to expansion and contraction of the sash and frame. Unbound from a large 1941 architectural catalog, this unique old two page technical brochure would display wonderful matted and framed. Nice graphics. A fabulous addition to your retro window weatherstrips library. Pages are detached and may contain a small amount of residual glue on edge.