I have been using a 7 led cluster bulb (you can buy them from most caving shops for about £30) in my Headlite. The problem that I have is that one or more of the individual led's have failed. I have 8 lamps that I use for work, so when one fails I take a bulb out of another lamp. I now have five duff bulbs out of my original 9. Can anyone tell me why they are failing. Some have failed completely, while others work, but at a much reduced brightness. Also can you tell me who makes them so I can send them back. The shop I bought them from (Quipu in Bristol) are no longer in business, so I need to return them to the maker.

I presume its a Speleotechnics 7-LED reflector? See www.speleo.co.uk

What battery have you been using with it?

No Paul, it is not a Speleotechnics reflector. The 7 led's are mounted on a single screw mount, so that the bulb simply replaces the halogen bulb in the headset. The led's are in a circle. The diameter of the complete bulb is about three quarters of an inch. The bulb does get very hot in use. Dragon, Inglesport and Hitch N Hike all sell these bulbs. I am using a Speleotechnics Headlite battery, the one with the green connector.