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umm.. look someone will say I am biased and want you to get my regs. But those are really cheap knockoffs of late 70's designs and while they may "work" I would be concerned regarding CO2 retention and flow rates. I have seen them in asia and haven't even bothered testing but did try one on a tank and the cracking effort was very high, easily 4+Not recommending these exactly, but it would appear that these are on Amazon too. Might be easier to buy there.
https://www.amazon.co.uk/OHQ-Adjustable-Regulator-Breathing-Equipment/dp/B07K1NY2LP/
https://www.amazon.co.uk/REAMTOP-Equipment-Regulator-Octopus-Mouthpiece/dp/B01M2AC0VX/
They are scary cheap though.
What everyone above is saying is that these are piece of panda dung not worthy of human use.
Service these next year?!? Why bother? At that price, they are disposable and cheaper to replace than to service. Like a really cheap digital watch that costs less than a replacement battery....I saw regs like those 2nd stages. Hanging on a shop wall in the early 80's - they were obsolete then.
Who's going to service your chinese knock-offs next year?