Dimensions: 4.37" x 4.37". FOV: 285-170ft. @ 1000yds. Porro prism. Actual magnification: 8.0-16.0x. Eye relief: 14-11mm. Objective clear aperture: 21mm. Center focus. Uni-body design enhances durability by locking objective lens in a single housing and synchronizing the eyepiece movement. Apherical lens elements assure the items on the edge of your field of view are just as sharp as those in the center. Focusing range: 10ft-infinity. Exit Pupil: 2.6-1.3mm. Eye Relief: 14-11mm. Relative Brightness: 6.7-1.7. Helicoid eyepiece ring. Color: Black.