I purchased this and along with the V-series dovetail bar to mount on top of my Celestron C11. I use this adapter to mount the Celestron finderscope. The adapter and the finderscope with the Celestron’s finder bracket combo weights in almost 2 lb. by sliding the finderscope back and forth on the dovetail I can balance the scope in DEC axis when I change from the heavy 30mm 2″ eyepiece to small 1.25″ eyepiece. Excellent product and excellent service.