These downlights which are excellent for kitchen use, require transformers. Low voltage lamps are not wired directly to the mains and a transformer is used to reduce the current to 12v which will give out less heat (great in the kitchen) and save you on electrical bills.
Transformers are available in a variety of different wattages but Lighting Styles recommends using one transformer per lamp/fitting as this makes replacement of a faulty transformer easier. New style electronic transformers are much more reliable than their predecessors and many of our transformers carry a 5-year guarantee.