For some reason these rollers have now been discontinued from the UK market and it doesn't look like they will return any time soon.
The Gizeh adjustable Rolling Machine is following a trend in rolling tobacco that others should have picked up on a good while ago. Many roll your own customers like a thin cigarette. Some because they like to save tobacco, some because they are strapped for smoking time in the cold weather and some simply because they prefer the character of a thinner cigarette.
The problem being that you wrap the paper round and round the tobacco meaning you are smoking more harsh tasting and harmful paper than you are tobacco. This affects the flavour and has been suggested is worse for your health, especially if they are cheap papers. Gizeh have been producing extra slim papers for a few years now and have enjoyed great success. However their success was slightly limited as some smokers find rolling a thinner cigarette is a bit fiddly.
So they decided to make it easier. The Gizeh Rolling machine is adjustable so you can roll a thinner cigarette by simply flicking the lever on the side. If you want it a bit thicker then turn the lever the other way.