I have tried different lenses, this original 2.1mm lens replaces the factory 2.5mm lens, I believe it the Eagle comes with the 2.5mm? Anyway, if you're not sure about switching to a 2.1mm, don't worry! I didn't notice any weird fisheye affect or anything like that! For me it made the world of difference! I'm new to fpv, I was currently flying in a huge field with the original lens but no I'm flying in and around my backyard and around the outside of my home!! Get the lens from RunCam, you won't regret it!!!