PORTLAND, Ore. -- The Mountain Locator Unit, developed for climbers on Mt. Hood, is retired and no longer available to rent.

The device came to life after a horrific tragedy on the mountain in 1986, in which nine people died, including several students from the Oregon Episcopal School. A brutal storm pummeled the mountain during the school’s annual climbing trip. The extreme conditions made it nearly impossible to see for three days.

Scott Russell helped with the search.

“It was extremely frustrating to know where they were within a quarter of a square mile but being buried under the snow they couldn't be found for days,” he said.

He turned frustration into action.

Russell found a company that made tracking units for bears and convinced them to make something for climbers on Mt. Hood.

A mountain locator unit.

“It was animal tracking, put on humans is what it was,” said Rocky Henderson, from Portland Mountain Rescue. “It was something different and new.”

Russell and others pushed through a thicket of issues to get the units made. They even convinced the Oregon Legislature to pass a bill addressing liability issues with the unit.

There was no turning back.

“We had the backing of parents who lost children on the mountain. How can you tell a parent that you're not gonna complete this job? You can't do it!” Russell said.

Two years after the disaster, the MLUs were ready for rent to Mt. Hood climbers.

In 1988, there was no cellphone and few people had ever heard of the internet.

The MLU used a radio signal that would go off when climbers activated it. Receivers held by rescue teams would direct them to the signal.

Over the years the units saved the lives of at least three climbers, according to Henderson from Portland Mountain Rescue.

“It wasn't the only solution but it definitely assisted in saving lives,” he said.

Henderson also said the MLUs changed the way climbers thought about risk on Mt. Hood.

“It made people stop and think, what was the big benefit? Like, 'well I don't want to get lost, so maybe I don't have a beacon but at least I’ll think twice about going in this weather,'” he said.

Now, nearly 30 years later, the units are outdated. Smaller, more powerful units like the ResQLink replaced the MLU.

“Its very simple to deploy,” said Guy Trombley, general manager of Mountain Shop in Northeast Portland.

“You flip the antenna up in this position, and you push this button right on the side and that activates the signal,” he said as he demonstrated with a unit. Mountain Shop rents the ResQLink rents for $30 for two nights and three days.

Its GPS abilities make it more powerful than the MLU. A powerful signal reaches up to satellites.

“And that ensures a signal even from a slot canyon, to get up to a satellite to relay the information to a local mission control center which then sends the message out to groups like Portland Mountain Rescue to come find you,” said Trombley.

The MLUs on Mt. Hood were years ahead of their time. But now time has caught up.