The counterweight rod is attached to the dovetail rail using a 1/4 inch photo screw.
It is compatible with the Vixen counterweights 1.0 kg, 1.9 kg, 2.8 kg and 3.7 kg and is used to balance the
AP Photoguiders, the Polarie or the Polarie U Star Tracker.
Shank diameter: 20mm
Size: diameter 23x135mm
Effective length of the counterweight rod: 130mm