The gyro-theodolite Gi-B3 was made in 1964. It consists of three units: a gyroscope unit, a theodolite unit and an electronic unit. The rotating spinner is positioned in the direction of the meridian, and the instrument can be used to measure the geographical azimuth. The instrument is useful in building tunnels, mining and other applications for staking out the direction, especially below the surface. The instrument needs to be oriented roughly before measurement, which is why it comes with a compass. It is equipped with an automatic gyroscope swing tracking mechanism and an analogue optical reading unit. The measurement time for one azimuth is approximately 25 minutes. The reading precision on a 90 mm diameter horizontal circle is 1'', the standard deviation of the measured angle is 1.5'' and the standard deviation of the measured azimuth is 5 - 8''. The instrument weighs a hefty 18.2 kg without the tripod and electronic unit. It is useful for measurements in the range ±75° latitude.

The instrument was used very little and is like new. Few individuals knew how to handle it. The instrument lacks a tribrach for tripod mounting and levelling.