Many experienced navigators prefer the plastic-framed Mark 25 to metal sextants for some very good reasons, and affordability is only one of them. The instruments light weight makes it easier to hold steady for accurate reading. Replaces the conventional half-silvered mirror with a full-field dielectric beam converger and combines horizon and celestial images in a single field for easy, reliable sights even in low light conditions. LED illumination floods the arc and drum with soft light for night use. Frame Material: Reinforced plastic, upgraded for stability Sighting System: Full-field beam converger Scope Magnification: 3 x 27mm Filter Shields: Seven large sunshades Arc Range: 120 to -5 of arc Drum Calibration: 2/10 minute of arc Lighting: LED Illumination Weight: 16.5oz. Case: Padded shock-resisting case Included Accessories: Well-written instructions and case Warranty: One year