This is a great box, originally envisaged by Sky to be a compact additional “Multiroom” box for folk with an existing subscription, however it is a fully fledged High Definition receiver capable of perfect reception, without either card or subscription, of at least 4 “public” FreeToAir HD channels, and over 200 other FreeToAir channels. Of course you can also use it with an existing SKY FreeSatFromSky card (eg to get you own regional BBC1 and ITV1) or indeed with an existing Sky Subscription card.
This particular box has been set up to receive Channel 5 HD in addition to the 4 Main FTA HD channels (BBC1 HD, BBC HD, ITV1 HD, Channel 4 HD).
Note that currently (December 2012) if you have a non-Sky FREESAT box (eg Bush, Humax etc) you cannot receive Channel 5 HD.
If you want Channel 5 HD from satellite you need a SKY box like this one, specially set up for Free To View (FTV) channels (or of course have a Sky subscription, a £25 "Freesat-from-Sky" card, or an active Sky card.)
The only way other way you can receive Channel 5 HD without subscription is online.