We regularly refer to Icage downlights as the Swiss army knife of downlights. This is because they meet every criteria that can be asked of a downlight, except they are not F-Capped Approval. Icage downlights will house any bulb and are supplied with both low voltage MR16 and mains voltage GU10 lamp holders. Simply dispose of the one you don't need.
The main advantage that the Icage has over basic fire rated downlights is that it is not fully enclosed at the back. Basic fire rated downlights have black fire cans which cuts off air and prevents the bulb from ventilating properly. In other words it stops the bulb from breathing. The Icage allows the bulb to breath, pre-longing the life expectancy.
This becomes more important when you are fitting expensive LED bulbs. If you are paying £23+ for LED bulbs such as the Philips Master LED GU10 that should last for 40,000 hours then you should expect it to last for 25 to 40 years.
Putting an LED inside a standard fire rated downlight will reduce the life expectancy similar to a person that smokes. Smoking reduces a persons life expectancy. Icage downlights are like none smokers who will generally live longer.
Icage downlights are now available as complete LED downlights from www.downlightsdirect.co.uk