Is that the old Tristar head? It doesn't look like the shiney new one I recently got from Rob Lumb. It might just be an old pic, but the Tristar P4 head has a black plastic protective ring around the front of the head.
Bought one of these and not that impressed supposed to have been 50w equivalent but light is quite poor compared to 50w in prohead, it was suggested it could be possible to upgrade led s.
Is this an easy job and fiancially worth it.
The best person to speak to is Rob Lumb, who is the UK importer of greenforce torches. The head being sold on that site is the old tristar head that gives out about 300 lumens; the newer version is the P4 tristar that gives out 660 lumens. I don't know if you could upgrade the LEDs, speak to Rob, and he'll tell you what is possible: http://www.yorkshire-divers.com/forums/members/rob-lumb.html