SUUNTO Tandem Compass and Clinometer Liquid-filled precision compass and clinometer for surveyors, cartographers, and others Ideal for accurately measuring directional indications, heights, vertical angles, and slopes Offers scales in both degrees (0 +/- 90 degrees) and percent (0 +/- 150 percent) 90-degree edges for contact measuring; water- and impact-resistant aluminum housing This item is not for sale in Catalina Island