You know how annoying it is: your mobile, which serves you well outdoors, at your office desk and - to fellow passengers' annoyance - on the bus, just doesn't get a strong enough signal at home.
Maybe you're in a basement flat, or maybe your living room is signal-free while you find that in your bathroom, and more specifically on the freezing cold window sill, your mobile boasts a full five bars.
If you're on Vodafone, help is at hand. The Sure Signal is effectively a tiny mobile phone mast that sits in your home. First things first, don't worry about frying your brain, the radiation is no greater than that of a wireless router. And it's near the router, actually, that you'll need to put this gizmo.
This is Vodafone's third-generation Sure Signal and is smaller than previous ones. It's designed to plug into the wall. You don't even lose a power point as there's a pass-through socket on the front.
First, you go online to register your Sure Signal, including adding the numbers of family members on Vodafone so the whole household can use it. Then, you plug it in and attach an Ethernet cable from the device to your broadband router.
And that's it. You're done. Everything else is automatic.
You can register up to 32 phone numbers to the Sure Signal - which is handy if you use it in your office, say - though only eight devices can access the Sure Signal at a time.
Once you're set up, your Vodafone mobiles, wireless modems and tablets will treat the Sure Signal as their nearest 3G transmitter. Theoretically, this should also improve your mobile devices' battery life. If you're in a poor signal area, a mobile spends energy and time checking for the strongest signal connection. Here, it's found it. Mind you, at home you're probably not far from a charger.
With your gadgets connected to the Sure Signal, the calls, text messages, emails and internet browsing are all routed via your home broadband automatically. You need to leave the Sure Signal switched on all the time, and your broadband router, though in practice this is unlikely to be a problem.
Additionally, Vodafone advises against using the built-in socket on the device for a high-power draw like an iron.
The range is claimed to be 30 metres and certainly in my tests it provided flawless coverage throughout the place I live - which by the way has so many girders built into it that I think it deflects mobile signals as completely as a Faraday cage.
Lights show when the Sure Signal is connected to your phone or tablet. But you don't really need those - the fact that you're making a call without trembling on the window sill is proof enough that it's working.
At £100 this is not a cheap gadget, and some will feel that it's up to Vodafone to provide perfect coverage. But if you're in need of a better signal, this is a quick, painless and efficient solution.
Vodafone Sure Signal, £100, vodafone.co.uk