Fits ours and most other FPV cameras with MTV mount. Lenses are a personal preference and given their low cost, many pilots keep a few around. 2.8mm is more narrow than a 2.5mm or 2.1mm. 2.8 is considered the "standard" lense type which is included with most FPV cameras.
You'll need to set the focus when you change lenses - just make sure you have access to some goggles or a monitor, set the focus at long distance and lock the lens in place with the locking ring.