One of the best bits of issue kit. The fact that you can today still be issued a bottle from the 1980s is testament to their strength. The bottles are impossible to destroy but I have had caps split but these are easily replaced. If you have a choice avoid the respirator compatible cap as (unless you want to use it with a respirator) its useless and the design is such that the cap detaches from the plastic keeper. I think most surplus ones would have the normal cap, but I don't know.