Ahh, fire extinguisher....I know a little bit about that, as I asked Phred the same question a few years ago.

The one you have weighs so much when it's new, and after all these years, it's supposed to weigh the same to be effective, more or less.

I'm sure Phred will explain this much better and in detail though.

I've had mine for at last 15 years, and I doubt I could lift it up very high if it was neccesary.

Stay safe!