We perform the tough environmental tests to ensure long-term operation even under the rough site environments. GM Series total stations are thoroughly inspected with dust-proof and water-proof test chambers. In addition, the various tests against vibration, drop, temperature, and humidity were successfully passed to achieve the best environmental spec. Also, the measuring distance accuracy test on base line and the instrument leveling and angle accuracy test and adjustment by collimator system ensure your satisfaction on GM Series product quality.