Olivon 12.5mm Plossl Illuminated Cordless Eyepiece. For guiding, higher precision GOTO alignments and collimation. This 4-element Plossl design is also well suited for off-axis guiders, where light gathering is minimal. Fully multi-coated lenses, 4° apparent field. LED-illuminated double crossline reticle has adjustable focus and brightness. SR-54 batteries included. 1.25″ diameter.