Newcon Sentinel (640) Thermal Binoculars 75mm lensThe Newcon Sentinel (640) Thermal Binoculars 75mm lens has a 75mm Germanium objective lens and a 640x480 pixel thermal sensor. This combination yields a detection range of more than 2500m (2700+ yards). With a thermal sensitivity of <40 mK at f 1. 0, the Sentinel (640) can detect objects day or night through fog, smoke, or camouflage, making it ideal for any sort of tactical observation, be it military, law enforcement, or search and rescue.