The PENTAX PF-100ED features a large 100mm objective lens for bright viewing under all light conditions. Featuring a straight-line optical barrel design, extra low dispersion (ED) optics incorporating Lanthanum Crown glass elements and waterproof construction, the PF-100ED provides durability and optimum optical resolution.

* The Pentax PF-100ED is housed in an exceptionally lightweight magnesium-alloy body. * Incorporating Extra-low Dispersion (ED) glass elements for optimum optical resolution. * Large 100mm objective lenses for bright viewing under all light conditions. * The body of the PF-100ED incorporates the American standard 1 1/4-inch (31.7mm) - diameter eyepiece receptacle, which accepts the Pentax XW eyepieces. * The receptacle has a special \"O\" ring assembly, which allows the body of the scope to be filled with nitrogen, making it fog proof and JIS Class 6 waterproof. * A built-in lens shade cuts excessive light and helps to prevent rain and other weather elements from interfering with viewing. * An extra wide focusing knob is incorporated for effortless focusing. * A tripod socket with a click-stop rotation mechanism is available to allow for different viewing angle options. * Famous Pentax Super-Multi-Coating maximizes light transmission, clarity and contrast. * An extendable eyecup on the XW eyepieces allows variable adjustment for up to a full 20mm of eye relief, allowing those wearing eyeglasses the same view as non-eyeglass wearers. * Equipped with a durable rubber housing to protect against shock and damage. * Lanthanum Crown (rare earth) glass elements. * The PF-100ED comes with a limited lifetime warranty. * The PF-100ED accepts the recommended PENTAX XW Telescope Eyepieces: XW7 (90X), XW10 (63X), XW14 (45X), XW20 (31.5X), and the Zoom Eyepiece (26X-78X).