Wood-built “stick” walls come in two sizes: 2x4 with plywood on the outside and drywall on the inside to create a wall thickness of 4 5/8 inches, and 2x6 that provides a total wall thickness of 6 5/8 inches. This makes it easy for window manufacturers to produce standard jamb depths. And since windows in wood-frame construction are always set in wood, installation is relatively easy. Many window manufacturers make installation even easier by attaching a plastic “fin” in the window jamb at the right depth. The fins come with predrilled holes for screws or nails, so workers can quickly position the windows flush with the wall surfaces and fasten them.