Yellow Trangia stuff sack. This particular one fits the 25 series kits. I have seen a couple others, but have no knowledge as to why they are yellow. Some speculation is that they were the first version of stuff sack offered, or that perhaps they were for the late 1980's/early 1990's red kits. Yellow on left, compared to a modern orange bag.
Kaw550Red was an early advocate of brightly-coloured stuff sacks to make them easy to spot among camping gear or in grass and using his tent-making skills he made sure his stuff sacks were the brightest around. It'd be nice to think that Trangia followed Brian's example.
I think the very early Trangia stuff sacks were actually sewn the same shape as the kit itself. With a metal zipper almost all around "the lid". I still have one on my old T27, bought it as a teenager way back in 1973-4-5 or so... Blue nylon, metallic zipper.
When were these bags introduced? I don't remember ever seeing one when I was in Scouts or doing my Duke of Edinburgh Award as a teenager or later into the eighties when I bought my own T27. I had a nearly 20 year break after that and got re-introduced to camping when my kids joined the Cubs. The bag and other useful wonders such as the multidisc seem to have appeared in the intervening years. Whatever the colour it does stop the carbon build up on the pan bottom rubbing off onto other things inside a backpack. Regards John
The only Trangia stuff bag I have ever seen, is one I found in the mountains few years ago. It had neigther of the two colors when I found it, but I think it originaly was red. My Trangia 27 from 1990 has never had any stuff bag.
I recently saw another yellow stuff sack, this time in an eBay auction for a (original) DuoSSAL kit. I don't know if this has any significance or not, being paired with a DuoSSAL.