I purchased these to hold my William Optics 50mm Guidescope with Rotolock, the exact scope these were apparently made for. They are well made, the finish is nice, they scope fits inside, but the rings do not firmly clamp the scope. Even with the rings tightened up more than I would want to, I can still twist the scope in the rings. I first noticed this when I was changing the USB cable on my guide camera and it rotated. At first I thought it was the Rotolock but it wasnt. The Camera was held securely but the entire guidescope had rotated in the rings. I maybe overly worried and I haven't managed a night guiding yet to test, but I worry when things get cold this will only get worse and any movement or rotation will throw off my guiding. Hopefully it won't but until I have verified it all, I am giving just 3 starts for the finish and expressing some concern over the fit.