I'm not a photography expert, but I do know that using filters can alter an image quite dramatically. My husband uses a digital SLR camera (fancy) but I use a compact digital camera or a phone. This filter can be used by either of us.This is a CPL (circular polarizing light) filter and there is a ring on the filter that when turned alters the ND (Neutral Density) setting - basically like putting sunglasses on the camera or phone to reduce the amount of light entering the lens without altering the colour, clever. I held the filter up to a light source (computer screen) and turned the ring - the amount of light allowed through the filter altered - the change is much more noticeable in real life. This should make a big difference when taking pictures where there is a lot of reflection, such as in sunny conditions or with water. This is a revelation to me, I had no idea such things exist for use on a phone!I like that the filter comes in a firm carry case to minimise scratching. The filter was easy to clip on and remove as required. I like it and it will be going to Kos with me in a couple of weeks where it should get a real test.FYI the pictures were taken on an iPhone 13 on a bright, sunny day with little cloud cover. I think there is a definite difference, but I think I need to play around and practice a bit more to get the best from this filter.At £17.99 (as at 10 May 2025) I think this is good value - even if I can't use it, my husband can on his fancy Nikon camera. Win, win.