Window manufacturer. For over 50 years, Trimline has provided quality custom windows for use in replacement, remodeling, new construction and historically certified rehabilitation projects. Trimline offers a wide variety of products including double hung, casement, bow, bay, awning, picture windows, and sash replacement kits, as well as round top, elliptical and other architectural window products. Custom colors in either all wood or aluminum clad exteriors and interior hardwoods of oak, cherry, and mahogany are available. Custom extruded panning systems and other trim accessories plus, a variety of simulated divided light as well as authentic true divided lite profiles, and replication of mullion details are some of our custom capabilities.