This is an alternative to the official DJI FOV Boost lens for the DJI Action 4/5 Pro cameras.As with the original FOV Boost lens, you swap the default lens with this one on the camera's body, then enable the "FOV Boost" option in the camera settings, and you can enjoy a much wider field of view for videos or photos. But beware, this forces the "fisheye" ("Wide"/"Ultra wide") modes –the camera disables the Dewarp mode once FOV is enabled, so if you thought that you could add this lens to gain a wider FOV and then dewarp it and end up with a wider linear video, sorry... this won't work (to be clear, this is a limitation of the camera and happens also with the original FOV Boost lens, not a limitation of the K&F Concept lens here).The kit is similar to the original FOV Boost lens, as it includes the lens itself and two plastic capr for the back and front, to fully enclose/protect the lens when not in use (the minor complaint here is that due to the difference in dimensions between the default and the FOV lens, the caps can't be used to protect the default lens that sits in your hands once you screw the FOV lens on the camera).I tried both this K&F Concept lens and the original DJI FOV Boost lens side by side, and I couldn't see a noticeable difference between their field of view, so I'd consider them equivalent technically (but do note that on paper the DJI lens claims 182 degrees FOV while K&F Concept claims 180 so there might be some small difference). Admittedly, I did not test for lens flare so I can't comment for any differences in this area). The lens adds 25 grams to the camera's weight (33g vs 8g of the default lens).So the lens could be a viable alternative to the original lens. But although you'd expect an after-market alternative to be cheaper as a motive to buy it, this lens currently sells for 65€ vs 59€ for the original(!), which means nobody will prefer to buy this one. I only deduct one star because of this; at around 40€, this could be a 5-star product.