You can call Tiara RV sales Elkhart In, they do Redwood parts and service, # 574-266-2136 0r email
Jennifer@TiaraRvSales.com she can probably help you but be sure you have Year, Model and Vin #, so she can give you part #, and order and ship for you if you so choose.
You can also then go to Steele Seals on Amazon and cross reference seal part # and check for a better price.