TM1500 high-precision telescope principle of hand-held laser range finder products: laser rangefinder generally adopt two ways to measure distance: pulse method and phase method. Method of pulse ranging is this: the process of the rangefinder emit; Laser is measured by the reflection of the object and then be rangefinder, laser rangefinder record at the same time from time. Half the speed of light and the product of the round-trip time, range finder and the distance between the object to be measured. Pulse method, the precision of measuring distance is usually in + / - About 1 meter. In addition, such a rangefinder measurement; The measuring blind area is generally 5 - About 15 meters. TM1500 high-precision telescope hand-held laser range finder product features: the instrument working wavelength of 905 nm and 1540 nm semiconductor laser. For 905 nm and 1540 nm laser range finder, we call it 'safety. YAG laser work wavelength of 1064 nm. The wavelength of 1064 nm is harm to human body skin and eyes, especially if the eyes are not careful to reach 1064 nm wavelength laser, the harm of eyes could be *. So, in a foreign country, a hand-held laser range finder, completely banned the 1064 nm laser. At home, some manufacturers and production of 1064 nm laser range finder. For the 1064 nm laser range finder, because it has potential harmfulness to human body, so we call it not safe '.