Aug. 4, 2011  -- Staff Sgt. Christopher Fessenden is on duty in Afghanistan now after tours with the Army in Iraq. He has traveled with standard-issue equipment -- weapons, helmet, uniform, boots and so forth -- plus a radio-controlled model truck his brother Ernie sent.

The truck is not a toy to him. He says it just saved six soldiers' lives.

"We cannot thank you enough," said Sgt. Fessenden in an email from the front that Ernie, a software engineer in Rochester, Minn., shared with ABC News.

The little truck was used by the troops to run ahead of them on patrols and look for roadside bombs. Fessenden has had it since 2007, when Ernie and Kevin Guy, the owner of the Everything Hobby shop in Rochester, rigged it with a wireless video camera and shipped it to him.

Last week, it paid off. Chris Fessenden said he had loaned the truck to a group of fellow soldiers, who used it to check the road ahead of them on a patrol. It got tangled in a trip wire connected to what Fessenden guesses could have been 500 lbs. of explosives. The bomb went off. The six soldiers controlling the truck from their Humvee were unhurt.

"Monday morning, Ernie comes running into my store and says, 'You're not going to believe this,'" said Guy, recounting the story in a telephone interview.

"I got an email from [Chris] that said, 'Hey, man, I'm sorry, but the truck is gone,'" said Ernie, admitting he still found it all pretty hard to believe. "The neat thing is that the guys in the Humvee were all right."

A Traxxis Stampede

The military does what it can to protect its troops in Iraq and Afghanistan -- they travel in armored vehicles and are trained in how to patrol for bombs -- but IEDs, or Improvised Explosive Devices, have been a constant danger. Ernie says he once asked Chris, "Doesn't the army have ways of checking for these things?" The answer: "If it does, I don't know about them."

That was what led Ernie and Kevin to send the model truck, a brand called a Traxxis Stampede. After they added the video camera, with a small monitor Chris could mount on his rifle, Kevin guesses the total cost came to about $500.

In his email, Chris Fessenden said the little truck has successfully found four IEDs since he first got it.

"We do mounted patrols, in trucks, and dismounted by foot," he wrote. "The funny thing is the Traxxis does faster speeds than the trucks we are operating in under the governing speed limit... so the traxxis actually keeps up with us and is able to advance past us and give us eyes on target before we get there."

"Is it a toy?" he wrote. "Yeah it is...is it fun... absolutely... but the guys here take the truck very seriously when out on [a] mission."

Replacement Truck on the Way

"I've talked to my brother a number of times and he says anything they get, from a letter to a bag of peanuts, it makes them feel great," said Ernie. "And then if you send them something cool like this, that helps them do their job and keeps them safe... There's just no way of explaining that. It's such a great feeling."

Kevin joined in: "For us, that's what it's all about -- a bunch of guys over there trying to make a difference."

They had already been trying to send Chris a new truck; the Stampede was wearing out. Kevin said he will donate one through a nonprofit group he helped organize, Fuel My Brain. They had tried to raise some money over the weekend at a county fair near Rochester, but had come away with all of six dollars. That was before they had a story to tell about the six soldiers.

"That's just unreal," said Kevin. "That's six mothers that six guys are going home to."

(ABC affiliate KAAL-TV contributed to this story.)