When James McCormick told armies, police forces and governments that his bomb detectors worked from 100ft underwater or a plane three miles up, it might have sounded too good to be true.
Especially when he added that they needed no power except the "electrostatic energy from the human body".
Still, he sold £37m (€43m) worth to Iraq at up to £27,000 per device. The UN paid £46,000 for five of them to find bombs in Lebanon. And there were many other customers.
In fact, the devices were £13 novelty golfball finders with no scientific basis and absolutely no ability to identify explosives, the Old Bailey in London heard yesterday.
McCormick (57), who bought a yacht and homes in Bath and Cyprus with the profits, faces jail after being found guilty of fraud.
He put many lives at risk, detectives said after the case. Thousands of the devices are still in use in Iraq.
McCormick is thought to have made £14m in five years from clients including the Kenyan police, Hong Kong's prison service, the Egyptian army, Thailand's border control and Saudi Arabia.
A former electrical salesman who had spent less than two years in Merseyside Police before failing his probationary period, he became involved after another businessman demonstrated a supposed prototype in 2000, the court heard.
He agreed to buy one for £10,000 and marketed the device to contacts around the world.
It consisted of a swivelling antenna connected to nothing except a plastic handgrip.
It was said to need no battery or other power source.
McCormick claimed the devices came to life after the user had shuffled their feet. Colour-coded cards were inserted depending on the substance to be detected: explosives, drugs, ivory, or even specific currencies.
But they were simply blank pieces of plastic containing no technology.
Experts told the court that the design lacked "any grounding in science, nor does it work in accordance with the known laws of physics".
McCormick, of Langport, Somerset, denied fraud, telling the jury: "I never had any negative results from customers."
He was granted conditional bail until sentencing on May 2. (© Daily Telegraph, London)