Most rings costing less than $25/pair have one or more fatal flaws: 1. Cheap screws that break when being torqued. 2. Variation in counterbore depth that can allow the cap screw to punch through the cap when being torqued. 3. Oversize ring diameter. These rings are often supplied with a thick fabric tape that does not cover the entire ring surface. These tapes compress over time, causing the ring to loosen, and they can leave a dent the scope tube.