These are great for Alcohol stoves.
They are very convenient and fairly reliable.
However, I wish this was made using more metal along with an o-ring instead of all plastic with an o-ring. The plastic just makes me worry to no end when backpacking. With alcohol evaporating so quickly and easily, faulty safety valve could easily ruin meal plans on a long weekend.
While it’s true I haven’t had a failure yet, it’s also true that I don’t want to be overly cautious with my gear, and this makes me worry constantly. So, one small star docked for that worry.
Even better would be a secondary outer cap going over this to reduce the chance (and worry) of the safety valve getting bumped.
There is a water filter bottle by Sawyer than illustrates what I mean by “secondary outer cap”. Looks sort of like those giant telescope observatories.