I had not thought about purchasing a part like this until I needed to. This cap is installed on the leading edge of the passenger side mounted awning facing the front of our rig, and it covers the gears that move the awning out and in. During a 4500-mile roundtrip to Colorado and back we heard something hit our rig that sounded like a rock hitting a windshield however we did not immediately see what hit where. After returning home we saw that this cap had a hole in the center of the leading edge with cracks spidering out around it. I assume a rock hit the center of it. Others report that the plastic eventually breaks down and cracks as well so mine could've been in this condition before our trip and I just hadn't noticed it.
This part comes in white only. Installation is simple, it just snaps on. My rig is silver, and I could leave it as is, but I purchased a rattle can of automotive plastic paint in the closest silver/gray I could find and its close enough once installed, I do not see any reason to perfectly match the paint unless you can easily find the paint match.
You do not want to travel far without this cap installed, something hitting the exposed gears, or just road crud getting into this mechanism will be a much more difficult and expensive fix. I purchased 2 of these covers/caps to have a spare immediately available assuming this will happen again in the future.
Nomadic Supply's site does an excellent job of helping you determine the part you need from the various awning specific
specifications illustrated in Fiamma's parts diagrams. After knowing the exact model number, the width (back to front) of the awning seems to be the most important specification that determines the correct part number. This is all documented in Nomadic Supply's Q&A on thier website. Given the global nature of Fiamma's install base you need to specify lots of things to determine which part you need, and Nomadic Supply helps guide you down the path to get to the correct part. I also contacted them to verify, and they got back to me quickly verifying that I was about to order the correct part.