You can also buy the Nicro solar powered vent-fan at any W. Marine. Just measure it to figure out if its a 3" or 4" wide model. Also make sure that the battery works to power it. Out of 4 Nicro fans that I've bought over the years, two had bad batteries that went out on me after only about a week's worth of usage. Nicro sounds a lot like Necro, latin for dead! (lol) Don't expect miracles out of these vents, but they do help to vent out smells from the head & do help to vent the cabin when it shut up during extended periods of storage/ dormancy.