A NEW device claimed to block up to 99 per cent of radiation emitted by mobile phones has been dismissed as all but useless by local scientists. About 8,000 Wave Shields have been sold in Hong Kong since they were launched a week ago, but experts say the $128 gadget will do little, if anything, to reduce the risk of ailments which could be linked to phone radiation. Their comments back the findings of Britain's Consumers Association, which told shoppers not to waste their money on radiation 'shields' after testing a range of similar products in April. The makers of Wave Shield, designed to be stuck on the ear piece of a phone, say the product has been tested by independent laboratories in the US and Japan and proven to 'block up to 99 per cent of electromagnetic radiation'. Ian Shelmerdine, chief executive of the Asian distributor, Wave Shield Ltd, said the patch was made of a 'secret' material - a treated cloth with metal inside it. He said it was the same material used to coat Stealth bombers. Depending on the model of phone, between 50 and 97 per cent of radiation was stopped from entering a user's ear, which he said was vital in preventing possible damage from electromagnetic waves. Mobile phones have not been proved to cause any ill effects, but anecdotal evidence has linked the radiation they emit to brain tumours, dizziness, headaches and a hot sensation on the side of the head. The Hong Kong Productivity Council's associate consultant on electro-magnetic compatibility testing, Wai Leong, said: 'It's useless, in our opinion. 'The material in the sticker may be okay, but . . . anybody who studied physics at secondary school will realise that something this small would be useless.' He said the wavelength of radiation emitted by mobiles was such that it could 'go around' something as small as Wave Shield. City University associate professor of electronic engineering Dr Tsang Kim-fung tested the Wave Shield on a popular Nokia mobile at the Post's request. He measured radiation levels where a user's head would be, both with and without the shield, and found 'only a minor difference'. 'Most of the radiation comes from the antenna, and if the antenna sticks out, there's no way to prevent the radiation at all,' he said. 'It only shields the radiation from the interior circuits that are under the label, but that's not where the majority of the radiation comes from.' Both Dr Tsang and Mr Wai said that if 99 per cent of a phone's radiation was blocked, users would be unable to make a call. 'If it really works, the phone wouldn't work,' Dr Tsang said. Britain's Consumers Association in April tested several models of radiation 'shields' made for mobile phones and found they provided no protection. 'The ones we looked at don't help, so if you're thinking of buying one, don't waste your money,' said Graeme Jacobs, editor of the association's Which? magazine. Wave Shield Ltd's Mr Shelmerdine acknowledged that many similar products were rip-offs: 'I agree they don't work. If you go around Shamshuipo you'll find about 30 or 40 of them - they're all useless. 'Anybody can sell a grid of steel and claim it's blocking the radiation, and gullible consumers will buy it.' But he insisted Wave Shield was different. 'I wouldn't knowingly or willingly ever sell something I didn't believe in,' he said, adding that he used the product himself and had found it stopped the hot sensation in his ear that he used to get during long conversations. Dr Tsang said it was possible the device blocked a lot of the radiation that would otherwise have gone through it, but said he would not buy it as waves entering the head, not just the ear, were of concern. The Post asked the US laboratory cited by Wave Shield, the American Society of Testing and Materials, to verify the company's claims but got no response.