Shed Windows and More Transom Window 10 x 18 Double Pane Insulated Double Pane Insulated Vinyl Mount Horizontal or Vertically Will Not warp, Peel, or Corrode - No Painting required 3/4" Nail / Screw Flange Maintenance Free rough cut 10-1/4" x 18-1/4", overall 11-1/2" x 19-1/2" x 3"