Extenders - For Sills Extenders provide an easy solution to extend any Pemko residential sill. Extenders fit all 5-degree sills. Made for 4-7/8" and 5-3/4" wide extrusions. Pemko EXT3/4_ Sill Extender Pemko EXT2_ Sill Extender Pemko EXT3_ Sill Extender