Just got one of the 9x23's back from D.R. Middlebrooks. He installed his new version of his Prosight. Very Nice. Its a small dovetail that goes front to rear with a allen screw to hold it in. It came with 3 replacement sights, a Tritium,white dot and a red fiber optic. All interchangable with a twist of the allen screw. The rear sight is still the low "V" like the Ashley. I took it out today and shot it...Love it. Its a Keeper!