This should be a fairly common item to get from the local RV parts store, as this is what you see on a lot of RV's nowadays. Worse call, you could call Tiffin, tell the year and model of your MH, and they can tell you exactly how much you need for the total number of windows having the issue. I just had them reseat some of the trim on mu 2 year old MH and I see more is shrinking, especially in the cold weather.