BLACKEAGLE Classic Aluminum Alloy Military Liquid Filled Lensatic Prismatic Compass with Pouch - Army Green aluminum alloy Imported Metallic liquid filled prismatic compass - military model Often used in connection with maps Lightweight and rugged aluminum alloy construction Has a foldable metal lid for easy storage and transport With a glass window & sighting line etched on the lid Sapphire bearing for ensuring quick movement, years of dependability, and optimal precision Prismatic readings avoid errors caused by mirror readings and potential parallax 360 rotatable bezel ring with scale for easy reading Liquid-filled prevents excessive oscillation of the magnet needle The liquid is extremely stable even exposed to extreme changes of temperature and air pressure Reference table at bottom of base for estimating distance and angle of slope Screw hole at base for fitting with a tripod Thumb ring for firm holding and neck strap Comes with a carrying bag and string