The ones I bought were actually MF-1T or "Micropur Forte".
I searched around Katadyn web site and apparently the plastic bottle container version of the tablets has a shorter shelf life (2-3 years) than the aluminium foil sheet version (5 years)
Micropur fact sheetAs far as I can see, the ingredients of these tablets are just silver ions combined with chlorine dioxide and it's in a pretty stable form. However, chlorine dioxide can cause explosions when mixed with ammonia compounds, so perhaps it's a good idea to remove those tablets from that enclosed air space with those batteries <img src="/images/graemlins/blush.gif" alt="" />
Incompatible chemicalsMany thanks for all the additional info and warnings. I would never have thought that there is a safety issue here, but I'm so glad it came up. Perhaps the match in that battery compartment isn't a good idea either. Back to the drawingboard...