Swan 83 APO, the latest spotting scope from William Optics with high quality STM coated APO objective; it boasts a high-power zoom eyepiece and waterproofing for all weather condition. This great spotting scope will please amateur birdwatchers and terrestrial and sky observers alike. Highly portable it is recommended for advanced birdwatchers who want the best from their instruments. Innovative Variable magnification (25x to 75x ) zoom eyepiece. Twist-up eyecup. Good eye relief: 19.5mm(25X)-18mm(75X). First 82 degree Ultra Wide Angle Eyepieces on Spotting scope market. Nitrogen Filled Nitrogen filled. Rubberized fit and finish and light weight aluminum construction. Rotatable 360 deg. on its axis for increased ease of use and comfort from any position. Retractable dewshield. Any Position Rotatable 360 deg. on its axis for increased ease of use and comfort from any position. Retractable dewshield. High-quality Lens 83 mm high-quality ED objective made with Japanese Ohara glass. True apochromatic performance. Bright and sharp to the edges. Excellent color rendition for nature viewing . Rubberized Green rubberized surface, ideal for outdoors activities and casual birdwatching. 　 　 Objective Lens Die (mm) 83 Objective type Doublet, Air Spaced, APO Magnifications 25X-75X Coating Fully multi-coated Field of View (degrees) 42°(25X)-66°(75X) Field of View (ft@1000yds) (m@1000m) 29.5m/88.5ft(25X) 15.5m/46.5ft(75X) Eye relief (mm) 19.5mm(25X)-18mm(75X) Exit pupil (mm) 3.3mm(25X)-1.1mm(75X) Near Focus (m/ft.) 7m/21ft Length (mm) 560 Weight w/eyepiece (kg/lbs) 2.770/6.107