The Trigon appeared in two versions. Both are adaptations of the Oldham caplamp, first Trigon had a copper based external heatsink mounted on top, from memory possibly same as the earlier UniStar. Main difference was that Eco was a low voltage lamp, Trigon was nominal 7.4V and mounted two series wired Cree XM-L leds as main light source and was therefore a lot more powerful.
The later version still mounted a top heatsink but was a lot lighter as it was based on a heat path which was a big aluminium plug that screwed in at the back where the charger socket would normally be. I took out a temporary patent on it and tried to sell the patent design, but no takers so I wasted my money.
I can supply battery packs that are backwards compatible and also offer a repair service on these.
A notable user is the author Michael Brown who has used one for years that he had bought SH off eBay! Its seen a lot of use, he has bought new batteries off me over the years.
In truth, they have to be considered an old design, more recent aluminium bodied lamps are much better. As with any product, the lamps have been subject to constant improvement. But the older Oldham conversions maybe have a charm all of their own. This opinion has been expressed by some owners.