Pentax XF Zoom Spotting Scope Eyepeice for PF-80ED, PF-80ED-A, PF-100ED. PF-65ED and PF-65ED-A Spotting Scopes Focal-length range of 6.5mm to 19.5mm Magnification of 20 to 60 times Apparent Field of view of 42 to 60 degrees Eye relief of 11mm to 15mm