I've used the SightLink made by MSP, and I like it for an iron sighted gun. It comes with several color fiber optics so you can choose which you like best. As I recall, there was red, yellow, green and orange? Up side is it sure does make your sight picture come in faster. Down side is it makes the sight a little larger and maybe no quite as accurate. But in my view, the better speed was a greater advantage. Other downside is ALL the fiber optic sights are no where near as durable. They will fall out with extended hard use. But the fiber optic is easy to replace, and all of them I've seen give you extra fiber optic to use when that happens.