With multiple divers and multiple cylinders knocking about on campsites and on diving trips like this, it's imperative first of all that cylinders are marked as your own. Thanks to Mark Emery at DiveSigns, we have beautifully marked name and MOD stickers on our cylinders so that at a glance, we know which ones belong to whom.
The next job is to make sure the gas is correct, by analysing it and labelling it up with a sticker which should sit on the curved shoulder of the cylinder.
Having analysed the gas and checked the bottle is full, you should write on the label: The date of analysis, your initials/signature, the pressure and the gas mix, including the decimal point. Writing down the decimal point indicates to the diver that they are about to breathe analysed gas - and not the gas they asked for at the shop!
Cave divers have a real interest in making sure those cylinders are full, as carrying them kilometers through arduous dry cave to only find that they are empty, amongst other things, doesn't earn you brownie points with your mates or sherpas!!