A 70° apparent field of view and 20mm eye relief deliver exceptionally powerful and clear images. Superior transmittance thanks to proprietary multi-coating. Waterproof for everyday use / [XW5] XW5. A 70° apparent field of view and 20mm eye relief deliver exceptionally powerful and clear images. All products feature a 70° apparent field of view and 20mm eye relief. Enjoy powerful star images with a wide field of view. New optical system for even higher performance. The optical system uses high-quality lanthanum-based high-refractive-index, low-dispersion glass. Advanced optical technology provides balanced correction of various aberrations. Considering spherical aberration in particular, PENTAX reduces blackouts from the field of view for improved visibility. Superior transmittance thanks to proprietary multi-coating. All lens surfaces that come into contact with the air utilize PENTAX's proprietary multi-coating, and bonding surfaces are also specially coated to achieve transmittance of over 90% across the entire visible light spectrum (approximately 96% at 550nm). Waterproof for everyday use* All products are waterproof for everyday use, so you can observe without worrying about getting wet during night dew. *Equivalent to JIS Class 4 protection, waterproof for everyday use. Cannot be used underwater. Sleeve size and eyecup mounting diameter are 31.7mm American size and 50.8mm 2-inch size. When the rotating eyecup is removed, a 43mm diameter/P0.75 thread is revealed. ■Specifications■Focal length: 5mm Lens construction: 5 groups, 8 elements Apparent field of view: 70° Eye relief: 20mm Mounting diameter: 31.7mm Size (maximum diameter x length): 61mm x 127mm Weight: 395g □Manufacturer's warranty period: 1 year