The Alpha Optics AO-5435/5465 thermal imaging clip-on system is one of the most advanced systems in its class. Displaying the thermal differences in the scene, the high-performance thermal imaging system of the device provides round-the-clock, all-weather detection and discrimination of heat-generating objects, including those that are hidden. The device is designed with the shutter-less calibration technology enabling quick start and continuous image without stops and delays. The specially developed control electronics of the device works without complicated menu. Ballistic corrections and four memory slots enable saving zeroing profiles for different distances and different types of ammunition. The AO-4465 is effective at close and long ranges regardless of light and weather conditions, such as in total darkness or through smoke, haze, fog, and light rain.