More than 30 years of research and development are built into every fully welded Pro-Tech 400 Series replacement window. The Pro-Tech 400 Series includes state-of-the-art design and advanced production techniques which offer a more stylish window backed with top performance ratings.

The technology behind the Pro-Tech 400 series replacement window includes advanced fabrication process which allows compound shapes to be fusion welded at sill corners, producing a window that is actually stronger than conventional welded windows.