From a processing perspective, there is nothing to complain about. Yes, if you plan presses from above, is to the material. But again: It's not safe, and therefore does not have to consist of break-proof material. Nevertheless, it is of course not so that you could damage the cartridge with a nail file or your bare hands. It is as resistant as they should be - no more, no less.
The castle is really only that the lid remains - of course it is very easy to crack. Think about it logically for: pick after a fire the cartridge out of the ashes, and then are faced with a burglarproof lock faced that prevents you from coming to the content, which is indeed intact, but also out of reach. Useful? Of course not. Therefore, the lock and the lock are designed so that they can break easily - even if everything is completely deformed by fire.
A4 documents fit easily into the cassette as indicated. Who wants to be sure to 1000%, the document additionally plugged into a document protection pocket, and all then in the cassette. Thus they should even survive a meteor strike - although after probably no one is there to read them. Example of such a case:
HMF 44141 Fireproof document bag document folder, ideal even in Safe A4, 38.5 x 26.0 cm
Allegedly, the cassette is only limited suitable for hard disks and USB sticks, but I'd rather keep it than anywhere else - unless you have a place that is more protected from fire.
The castle was compared with their predecessors apparently improved - there is now not a normal key longer necessary, but a round. I do not know how they call these locks, but you can see for the product images. Also bike locks like to use this type of lock. I had previously not once trouble opening or closing. As for the safety of the castle, see above.
The problem with the "sweating", the other fire protection tapes have apparently does not exist in this. Even if one does not open the cassette several months, it is straw inside. And my apartment is more humid - if so with me not collect any moisture, then also with other not. Except maybe in a sauna or a terrarium).
Of course I can not say anything about how the cartridge behaves in an emergency (thankfully!). On YouTube and also by the manufacturer, there are test videos, so I simply want to trust the promises - it is a yes and no choice except to buy up as a cassette for testing, and flaring it somewhere controlled manner.
Only handles would have been really helpful - the other reviewers have indeed been criticized.
All in all, I can tape but definitely recommend.