The telescope eyepiece design is superior to the Plossl for lunar and planetary study. Beautiful black anodized machine work threaded for color filters. Fully multi coated with rubber eyecups. These reasonably priced oculars will become your "workhorse" when you want a sharp, clear image. Available in 4.8mm, 7.7mm, 10.5mm, 16.8mm, and 24mm.