The classic design, the model 12603 meets the high standard of accuracy in prescription lens measurement. The illumination system provides sufficient light for even the darkest ophthalmic lenses and its target configuration brings added precision in reading low power cylinders. The long (6") lens table handles any size frame, and may be smoothly positioned by a positive action cam and lever; it will also accommodate large uncut lenses. The high eyepoint design allows the user to wear glasses without cutting off the field of view.A recessed lens protects against scratching. The focusing eyepiece features a reference scale for quick, accurate reset without visual refocusing. A dual knurled power wheel with high contrast scale provides easy, one-handed operation. Ready-mark lens marker facilitates inking and marking. A large instrument base assures excellent stability and comfortable wrist support. Enclosed bearings.