Properly balance your OTA and accessories on GM-8, G-9, G-11 and Titan EQ mounts with this Losmandy 7-lb Counterweight. When used alone or stacked with other weights, you will relieve stress on the mount's gears, while making it easier to move for smooth tracking. The center bore hole is sized to fit the counterweight shaft and a thumbscrew allows the weight to be locked into position anywhere along the shaft for precision balancing.