Celestron's Night Vision Flashlight is a purpose-built astronomy illumination tool that uses two red LEDs to preserve night-adjusted vision while providing light to set up, read/write notes, change eyepieces, or navigate. Its combined rotary variable brightness control/on-off switch allows you to adjust the brightness over a wide range up to 25 lumens.
At the maximum brightness setting, the emitted light is bright enough to locate dropped items or disassemble your telescope after observing. The medium brightness levels will properly illuminate a star chart without affecting your pupil's darkness-adapted dilation. At the lowest brightness setting, there's just enough light to determine a filter designation or an eyepiece's focal length.
The Night Vision Flashlight is powered by a single 9-volt battery that lasts for up to 12 hours on high and as long as 300 hours on low The supplied 20" (51cm) cord allows you to hang the light around your neck when not in use.