This device was trailed in the Sunday Times on 3 October www.handsfreetechnology.co.uk/ , and is mounted on the metal posts of the driver's headrest, with a speaker next to the door and a boom-mounted microphone towards the middle of the car.  Easily mounted/removed. Works off 3 x AA batteries which "could last six months". That's the good news. 
 
The bad news is it costs £99.99 "plus p&p" (amount unspecified), will need the mobile phone to be mounted somewhere (on the dashboard?) for use, and so a wire (supplied) will need to be run from the headrest to the phone, and there is no provision for charging the phone. 
 
If it had been a third, or even half, the price I'd probably be interested.  Probably it cost $99.99 in the US, using the traditional conversion rate. 
 
Has anyone any experience of the device?  All the press comments date from early-mid 2002...
                            
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                        Various options 
 
If your phone has bluetooth then one of these or similar  
 
 cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=...1 
 
Or if its an older style Nokia, plenty of the hard wired kits flying around on ebay. 
 
Or my choice. I have a jabra Bluetooth headset. Supremely comfortable, can answer the phone or make voice activated calls just with a touch of the button on the ear.
                            
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                        I too am a convert to bluetooth, I've got a headset which came FOC with my phone (motorola V600)  
 
The other advantage is that you can use it as a handsfree outside of the car too. 
 
The downside? i look like a right chimp whilst wearing it and feel i should now buy a BMW 318i to finish the look off!
                            
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                        I have a bluetooth earpiece but, until my recent car change, have always used a hard wired kit. The disadvantages of bluetooth in a car are 1) it won't carge your battery; you have to plug in a separate charger cable and 2) you can't connect an external antenna. Considering that Nokia CARK-91 kits are sub £20 on ebay, I can't see the attraction of bluetooth. 
 
If you want to spend £100, Halfords are still doing their bluetooth fitted kit for £99.99.  
   
Hawkeye
 
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Stranger in a strange land
                            
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                        If you live in the North West and are near a B and M discout store, you can buy hands-free phone kits for as little as £1.99 (no recharging though) and a Samsung offering (caters for most mobiles and recharges) for £3.99...:-) 
 
The stores used to sell such kits for around £7.99, then £4.99 and now even less.
                            
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                         I can't see the attraction of bluetooth.  
 
I work for a main dealer and so i'm in and out of different cars all day long therefore a Bluetooth headset is ideal for me.
                            
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                        Hmmm.  Doesn't look as if anyone has bought one of these devices!
                            
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                        HF300? - I just wish these people had had the courtesy to give me some promise of commission before nicking my name. ;) 
                            
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                        Similar to what you describe - windscreen mounted and with an inernal battery - but only £22, and the reviews I've read seem to give it a thumbs-up: www.mobilefun.co.uk/product/1831.htm
                            
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