The Z-Axis Balancing Kit from iOptron can be used with mounts that incorporate an M8 threaded hole, dovetail saddle, or counterweight. It is a specially designed counterweight kit for Z-axis balance.
Compatible with the CEM120, CEM70, CEM40 (6" V/D dual saddle with an M8 threaded hole), and GEM45 (6" V/D dual saddle with an M8 threaded hole)
It can also be used for other mounts with an M8 threaded hole, a dovetail saddle, or a counterweight