Ok, from the rating and the title you may be confused about what I think of this item, but I really do love it - the title is because I want to highlight the fact that this box is not what I would call a splitter. What this box does, is enable those of you with nice posh TV and computer and broadband internet, to hook up, both the TV and the computer monitor so that at the push of a button, you can watch iplayer or whatever on the TV. You will not be able to watch the computer monitor at the same time, that will go blank as soon as you press the button, and you will only see the images on the TV. When you want to return to using your TV normally or to use your computer with its monitor, you just press the other button. It does not require a power supply.
To set up this box, you will need a good length of cable with VGA sockets at each end, going from the box to your TV, and another lead which will from the box to your monitor. The existing lead you have for your computer to monitor is going to go to the box and act as a feed. You are also going to need, depending on the type of leads you use, some female to female and male to male 15 pin converters also known as gender changers. I ended up using one of each with my cables. They are cheap and the company I bought this box from supplies them. This box is cheap and will stop you having to mess around with VGA sockets and cables all the time, so it is a real time saver.