I also want to say I phoned a local FE supplier, and when I said do you sell CO2 FE to the public he kind of laughed and said yes we do, then I said how much is the price for one, he said £54 and that's refurbished with new hose etc, I said what that's a 2KG Fire extinguisher he said yes it is, I said do you not have nothing cheaper for me like any thing about to expire etc, he goes what building is this for, I said my house he goes ohhh right, and can I ask what you need it for, I said CO2 for my aquarium, he goes ohhhh your thinking about this all wrong, you don't want a CO2 extinguisher the pressure is colossal, you need to contact a aquarium specialist shop right away as I know what it is you want to do, but this is not the way at all, so I just said oh right ok I understand, bye.