Orion ONE21 10mm Explorer II, 1.25" Kellner Eyepiece with 50 Degree Field of View.

The Orion 10mm Explorer II Eyepiece features the 3-element glass lens configuration which provides a pleasing 50° apparent field of view, wider than that of many pricier eyepiece designs. The lenses are carefully ground and polished from quality optical glass to provide excellent image sharpness and brightness. It is fully coated with anti-reflection material to maximize transmission of incoming light.

The anodized aluminum barrel is precisely machined and internally blackened to prevent stray light reflections. It's also threaded to accept standard light-pollution and color filters. Whether you're looking to upgrade from a lower-quality eyepiece, or you just want a good, reliable ocular at a reasonable price, you can't go wrong with Explorer II.