This filter is called Amethyst which means it should be purple or violet but it just looks blue to me but what a lovely blue. What’s important is that it does appear to improve the sight picture but I don’t know why. I can’t guarantee that the colour is reproduced accurately on your computer, (it looks fine on mine) but it must be worth a try. If I get any feedback I’ll pass it on. Once again we keep the 25mm in stock but the other sizes are available.