Lensmeter Corona Target combines an excellent Ocular Type External Reading System with very clear target screen. The instrument can be moved from 30° to 90° for getting an exact view of the corona. It also consists of High Power Magnification for sharp and bright corona focus. Specifications Type : Ocular Type External Reading System Vertex Power Range : ± 25D Step : 0.25D Step Up to± 10D 0.50D Step Beyond ± 10D Cylindrical Axis Scale : 0 to 180° (1° step) Prismatic Power Range : 5 in the View field (1 step) Target : Pinhole Corona Eyepiece Focusing : + 3D to -5D Diameter Of Lens Accommodated : 30 to 80mm Tilting Angle : 30° to 90° Light Source : AC 220V 3W LED