Infra-Red light for use with your night vision equipment. Cannot be seen with the naked eye. Small, handy unit delivers infared light so your night vision equipment can be used in total darkness. Uses revolutionary advanced energy control to keep this light burning for 41 consistent hours and the bulb never needs replacing. Includes a lanyard and metal clip for easy carry; waterproof down to 10 feet and uses 1 AA battery, not included. This is a great reliable Infra-Red light!