The ML1's LED light source ensures that you will never need to change bulbs again. The comfortable glare-free, green illumination and sharp mires make measurements easy. Battery operated and completely cordless, the ML1 Manual Lensometer gives you total mobility and no cord clutter. The LED's low power consumption and auto sleep feature ensure a long battery life. The standard AAA batteries are inexpensive and available everywhere. The ML1 can be adjusted to any angle, providing maximum convenience while measuring. Full 90 degrees tilting allows for easy measurement of contact lenses. The ML1 can measure lenses from 24 to 90mm in diameter and uses a bold crossline target for easier reading.The prism compensator extends the range to 15 diopters for more flexibility.The Reichert name ensures a high quality, reliable instrument that you can count on every time.