Things I liked: It does the job it was intended for and unlike the 1 piece fixed dovetail stops, does not require the rings to be removed to slide on the stop. It can be put on with the rings still mounted (sans scope) but the roll pin will have to be tapped upwards and out of the way to allow the fixed dovetail side to slide into the groove.
Things I would have changed: Things i would change. I would make the edges of the dovetails sharper for more surface area contact. I also would change the roll pin to an Allen bolt, but because different guns have different scope stop hold depths, I'd provide several thin steel washers of varying thicknesses so that the Allen bolt can be spaced so deep enough to provide maximum surface area contact, but not touch any moving parts such as the bolt. Still, it does the job it's supposed to and I have no complaints.
What others should know: It would not just slip on as the pin's position as it was prevented the scope stop from just sliding on. I had to use a punch to push the roll pin upward to get the fixed dovetail side onto the dovetail rail of the rifle. Once the fixed side was in place, I then slid the stop to the position I wanted it to be and made sure that the roll pin had sufficient clearance so that when it was finally pushed into the stop hole, it would not gall any edges. i then semi tightened the 2 locking Allen bolts on the side and then tapped the roll pin into the hole, then loosened the locking bolts just enough so that the scope stop could be slid with some resistance and pushed the scope stop as far rearward as it could go (the roll pin now contacting the rear surface area of the hole it's in) then tightened the locking bolts.