... maximum light transmissionModels available for CT long eye relief series:7x35, 8x40, 7x50, 10x50, 12x50, 10x60, 12x60; zoom models: 7-15x35 ... , 408ft at 1000ydsEye relief: 11.8mmExit pupil: 5mmRelative brightness: 25 7X35 long eye relief binoculars