OO/4mm/1:76LX171-OO ARCH TOP INDUSTRIAL WINDOWS WITH HEADERS & SILLS Laser Cut Self-Assembly Kit For OO Scale Model Railway LayoutsA pack of 12 laser cut & engraved 20mm x 24mm arch-top industrial windows complete with sills & header stones for scratchbuilding & upgrading existing buildings & kits. Cut & engraved from 0.8mm laseboard for a realistic appearance once installed .Simply remove from the sheet & they're ready to paint & install as required. Sills have an additional scored section which can be folded back into the window aperture if required. Alternatively this can be carefully trimmed away if not required.