Whether you need to signal for help or just want to locate a reflective object in the dark, the Rescue Laser Light is the incredibly versatile, easy-to-use tool that does it all. This multi-purpose device is waterproof, environmentally safe, and does not pose a fire hazard. Its red laser diode can be seen up to 3 miles away during daylight hours and over 20 miles away at night. Its simple twist-on/twist-off operation, light weight (3 oz.), and compact size make it easy to use whenever needed. A single CR123 3-volt Lithium battery provides up to 40 hours of reliable power. A safe, simple, and dependable source of illumination.