There isn't much to replace an RV Vent Lid. They all pretty much work the same way, and the difference that you need to know is which style of Hinge the Vent has. The hinge dictates which lid you need, period.
Eric from the Smart RVer Podcast shows each Lid and Hinge type in this video so you, The Smart Rver, will be able to sound like an expert when it is time to replace the RV Vent Lid. Eric is also an expert on Escape Hatch lids. A video will be coming soon.
www.thesmartrverpodcast.com