Pentax Eyepiece SMC Waterproof Zoom 8mm-24mm 1.25 Tube. Specifications for Pentax 20x-60x Zoom Eyepiece 70509 Magnification: 20x-60x Lens Structure: 6 elements 4 groups Real Field of View: 1.9 Degrees - 1 Degree Apparent Field of View: 38 Degrees - 60 Degrees Field of View at 1000 m: 33-17m Field of View at 1000 yd: 108-56 ft. Exit Pupil: 4-1.3mm Eye Relief: 20mm Relative Brightness: 16-1.7 Eyepiece Size: 5.7 x 2.7 in. Lens & Outside Diameter: (144 x 69mm) Weight (Eyepiece): 19.2 (550g) Specifications for Pentax Eyepiece SMC Waterproof Zoom 8mm-24mm: Manufacturer: Pentax Condition: New Size: One Size Features of Pentax Eyepiece SMC Waterproof Zoom 8mm-24mm Compatible with the following: PF-65 and PF-65ED(A)II series spotting scopes PF-80 series spotting scopes PF-100 series spotting scopes. Package Contents: Pentax Eyepiece SMC Waterproof Zoom 8mm-24mm Pentax 70509: Eyepiece SMC Waterproof Zoom 8mm-24mm 1.25 Tube