There's one important thing to note about the ATX-200. It isn't EN250 compliant straight out of the box. It has some freezing problems in the second stage. When the EN250 requirements were first published, I don't believe any of the Apeks seconds passed. So, they added a small tab to the end of the balance chamber so that it was essentially like the adjustment knob was turned in about 1 rotation. Then, the regs passed EN250, but it made the reg harder to breath (a little). To improve performance, the tab can be cut off, but all Apeks regs other than the ATX-200 are EN250 compliant.
On the ATX-200, they took the opposite approach. The tab is not there, so it's not compliant. Instead, the adjustment knob has a little black insert in it that can be turned so a tab extends from it and pushes in on the balance chamber. The outside black cap needs to be removed from the adjustment screw and hex screw turned 1/2 turn clockwise. There are two o-rings in there that should be replaced, but usually aren't.
So, I would say, if you're planning to use the reg in situations where you may encounter freezing, extend the tab....
MD
On the ATX-200, they took the opposite approach. The tab is not there, so it's not compliant. Instead, the adjustment knob has a little black insert in it that can be turned so a tab extends from it and pushes in on the balance chamber. The outside black cap needs to be removed from the adjustment screw and hex screw turned 1/2 turn clockwise. There are two o-rings in there that should be replaced, but usually aren't.
So, I would say, if you're planning to use the reg in situations where you may encounter freezing, extend the tab....
MD
