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We’re all pretty familiar with the standard white light flashlights we use to illuminate dark areas, but did you know that flashlights come in many different types? One such is a red light flashlight, which is a more specialized variety mainly used to preserve night vision. A red light has the longest wavelength of all colors on the visible spectrum, around 700 nanometers. It’s much less disruptive to human eyes and produces less glare compared to traditional white light.

These characteristics make a red light flashlight an excellent choice for astronomy and similar night activities. Science says that rhodopsin (a light-sensitive protein found in the retina that is responsible for our vision in dim light) isn’t affected by deep red light. In other words, our eyes don’t get temporarily blinded or need adjusting, as is the case with white light in the dark. Because of this, astronomers use red light flashlights to read star charts or adjust telescopes without ruining their dark-adapted vision. So, make sure you take a red light flashlight with you as one of the gadgets when you go stargazing.

Since a red light preserves night vision, a red light flashlight has found its place in law enforcement as well. For instance, at night, police officers can use it to check paperwork or ID without temporarily blinding themselves or impairing their vision. A red light flashlight can also be used for signaling purposes, given that it’s less conspicuous than a white light. The military employs it similarly, for tactical operations that require subtlety and stealth. You can buy a specialized military flashlight yourself if you want to feel like a Ranger for a bit.

Other uses for a red flashlight involve hunting and wildlife observation. Because many mammals can’t see colors the same way humans do (and as such, fail to recognize red), using a red flashlight will make them less likely to be startled or scatter. It will also prevent any interference with the animals’ usual activities, such as their own hunting. This makes a red light flashlight (or another source of red light) an invaluable hunting gadget.