Single NdFeB magnet resists demagnetization better than other types of magnets for increased reliability Azimuth accuracy ±1/2° with 1° graduations Vertical accuracy ±1/2° with 1° graduations and 10 minute readability Vertical angle measurements to ±90° or 100% grade A percent grade scale with increments of 5% Induction damped needle for quick, accurate readings Sapphire jewel bearing allows for smooth needle movement Magnetic declination adjustment allows for east or west declination setting to 180° Short and long sights for increased accuracy when sighting azimuth or vertical angles Precision aligned mirror with convenient "see through" sighting capability Composite body material is permanently impregnated with color O-rings make the Com-Pro waterproof for increased reliability