The Greatland Laser Rescue Laser Signal is a nighttime signaling device visible up to 20 miles (32 km) away, and effective in daytime up to 3 miles. It is waterproof to 80 feet (3 m), and runs 40 hours on an easily replaceable 3-volt lithium CR123 battery. Other features include:

* Compact - fits in your pocket or on a keychain.
* Non Flammable, Environmentally Safe
* Rugged, machined aluminum with knurled design.
* Anodized for improved corrosion resistance.

It uses a long life laser diode - 10,000 hours (on average) to failure, and it offers a Limited Lifetime Warranty. Detailed warranty, registration and operating instructions are included with product. It is 3.125" long