Kolbe Vinyl Windows' Decorative Windows, built from the Inspiration Series double-hung studio/transom profile, is offered in many geometric shapes including octagons, full circles, gothics, circle tops, ovals and segment unit heads. The seam of the mulichambered PVC extrusions have been fusion-welded, preventing the infiltration of air and water. The overall frame width is 4 9/16 in. An integral 1- 1/4-in. prepunched vinyl nailing fin makes the unit easy to install while helping to seal the window to the wall. Extension jambs, available as an option in either wood or white vinyl, allow for an easy fit. Oak or pine casting is also offered.