Over time your granite lantern wood windows will deteriorate and possibly start falling apart. Many times they simply get lost. And yes, they are difficult to replace as each granite lantern is unique in its exact measurements. Japanese Style can now custom make replacement wood windows in our shop as needed. When ordering you can forward a photo with exact measurements to firstname.lastname@example.org, or mail to us the old window and we will replicate it. We laser cut each window for accuracy and perfect craftsmanship. Replacement windows will be slightly larger for hand sanding to fit exactly into your lantern openings (sand paper not included).