DENVER -- Experts say a new personal locator beacon known as the Spot Satellite Messenger might be the most exciting tracking device to hit the market in a long time.

Spot is said to be the world's first satellite messenger.

"It provides emergency services for the outdoor enthusiast," said Gordon Abrams, president of G_Wireless Consulting in Denver.

Spot messenger gives those exploring and enjoying the wilderness a vital line of communication, independent of cell phone coverage, through satellites.

The device has four buttons. An on-off button, and three other buttons to be used in varying degrees of need.

"One is the OK button, one is the 911 button and one is the help button," said Abrams.

The OK button lets friends and family know through an e-mail and/or text message that you are OK. The help button lets friends and family know that you need help. It also gives them your latitude and longitude and tells them the closest town to your location. It also sends them a link to Google maps and pinpoints your exact location on a map.

The 911 button is for those in serious trouble, described as situations where loss of life, limb or eyesight appears imminent.

The product is widely acclaimed by Colorado search and rescue teams. However, experts warn that traveling with the device does not make you more experienced or invincible, especially in the winter months when conditions in the high country can be deadly.

"It is important to remember all of these devices are used as a last resort," said Howard Paul, spokesman for the Colorado Search and Rescue Board. Paul tested a Spot device and said it worked well.

The device retails for about $150. There is also a $100 annual service fee.

Paul said the device is user-friendly, but he warns: "You shouldn't use one to put yourself in a position of greater risk or more danger."

They are transmitters only, a one-way communication device.

Calls to 911 locate the nearest emergency response group to the lost or trapped party's location.

Users write their own messages ahead of time for each button. Those messages are then sent from a computer to the system.

"You yourself go into your computer and log in and tell the system what you want your message to say and who you want the message sent to if you're in trouble," said Abrams.

Some terrain and adverse weather conditions can create trouble for the device. Abrams said deep and/or narrow canyons, thick forests and heavy snowstorms could block messages.

"It definitely has to have sight up to the sky."

They are very rugged and durable devices, weighing less than a pound and easily attachable to any article of clothing.

For more information, go to GWirelessConsulting.com.