The 28 Er is designed to be a light weight high performance eyepiece. It features anti-reflection multi coatings to control flare and ghosting. True to the original 5-element design, the viewer is presented with a flat field of view of 60°degrees across. Weighing a little less than 5 oz. the eyepiece is a light weight for a wide field eyepieces and can be easily used with turret holders and has been designed to be par focal with the Takahashi Abbe Series.