Natural wood interiors. Attractive low maintenance Perma-Shield® exteriors. Larger glass area lets in more light. Vinyl cladding protects entire sash from rain. Smooth Control™ handle hardware opens easily. Dual-pane insulating glass for optimum temperature control. High-tech weatherstripping. Wide range of sizes. Variety of grilles & insect screen options. Renowned limited warranty. One of the largest service networks in the industry.