This excellent instrument is easy to set up and easy to use and is designed for students to make precise measurements. This unit features high quality 22MM optics, a built-in illuminated auto-collimator for fast set up, a 17.8 cm diameter divided circle with clear gradations, a double-ended vernier with illuminated magnifier reading to 1' resolution, and a 7cm diameter prism table which rotates 360 degrees and adjusts 2 cm in height for any size of accessories.