Adjusting this review up to 4 stars. The newest version of this scope ring has a narrower dovetail snd fits down to 3/8 (10mm) Older versions were 11mm and would not adjust to smaller dovetails. Bravo to Vector for omprovong their products over time!These are alright. But unlike other variable height rings I have purchased, there are no “ridges” (like a ruffles potato chip) on the elevation adjustment mating surface to lock the elevation. (And to ensure you have the front and back rings the same height). So the only thing keeping the scope elevation locked is the tension on the bolts. This means you have to tighten them down a LOT to keep the scope height where you set it. In practice it stays tight for a while and then eventually it gets bumped and the point of aim is off. Plus with no defined ridges the only 2 height settings where you KNOW the scope is aligned are – all the way up, and all the way down…For those reasons I am giving this item 3 stars, it works but the inability to reliably lock the height adjustment is annoying (and for a hunting gun could actually be dangerous.)