Brunton O.S.S. 70M (Orbital Sighting System) Baseplate Compass. 4" x 2 3/4" x 7/8". Black and gray composition housing. Mirrored professional compass with map magnifier. Tool-free declination adjustment. Numerous map scales with interchangeable scale cards. Triple clinometer system. Magnified read out, 1 degree resolution. Orienteering lines. Blue nylon lanyard.