Fits Vixen Dovetail Plates V2A Stainless Steel Used for properly balancing your optical tube assembly (OTA), the Alpine Astronomical Baader 1kg/2.2lb Leveling Counterweight is made to fit Vixen-style rails. Unlike conventional counterweights that normally balance the OTA on an equatorial mount, this leveling weight attaches to the OTA’s dovetail plate and counters the weight of large primary mirrors on reflectors or Cassegrains on fork mounts to relieve stress on the motors and reduce vibrations.