Lightweight, cordless models can be carried any place. No cord to obstruct handling the lens meter Also, now you can use our LM-15 with an AC adapter! Features?New refined appearance with convenience-oriented design ensures operational ease. ?Troublesome lamp replacement is eliminated by an LED light source. ?The auto power-off function maximizes battery life even when the OFF-switch is forgotten. The batteries run for more than 200 hours continuously, and the power-off time is adjustable (2-6 min.). ?Can be clamped at any angle within from 45°?90°allowing measurement while in a comfortable position. ?Can be tilted to a full 90°for easy measurement of contact lenses. ?When an AC adapter is connected, the battery supply circuit is automatically closed to save battery life.