These are great - Hexion Tech Hexion Tech Seeker 1x 17.85-26 mm Reflex Red Dot Sight

I have a few of them because they work well, especially for the price—think of it as a trijicon rmr on a budget. They shoot just as accurately as my higher end optics. They feel solid, but I’m sure the price difference comes from the durability between this optic and a higher priced one. Basically, if you have an expensive high end gun, put a high end optics on it, but if you want a budget optic that functions well to put on your extra less expensive gun, then buy this instead, you won’t be disappointed