Large, easily adjusted mirrors using new instrument-quality glass and a special baked on salt-spray resistant backing. Both mirrors have protective housings. Horizon mirror is half-silvered. No adjustment wrenches required. Molded of high-impact, weather-resistant plastic. All Davis Master Sextants feature the following professional specifications: -7" (1 78mm) frame radius. Graduation 120deg to -5deg -Index mirror rectangular, 1.98" x 1.49" (50 x 38mm). -Precision machined slow travel gear and worm mechanism. -Highly visible, easy-to-read micrometer drum and vernier allowing readings to 2/10 minute of arc. -Fully ribbed, three-circle sextant body for platform strength and stability. -Large, contoured handle designed for sure, steady grip and angled back for added control. -Seven large sunshades allow complete, independent adjustment of shading density for horizon and index mirrors. -3 x 27mm star telescope with anti-reflective coated glass lenses, plus separate hooded sight tube for glare-free sun shots. -Neck lanyard frees hand and protects sextant. -Tough, fully padded, shock-resisting carrying case with compartments for extra batteries and mirror kits.