Mini Oxygen regulator question

[Cameronl]

Before I drop $12 on a bottle of O2, I need to find out if there's a problem with the regulator I was given. This is the one.

The knob doesn't turn. But it says on it "Do not force knob". So does that mean it doesn't turn when it's not attached to the bottle? Or is it seized with age?

-Cameron

 

[Cameronl]

Well, I broke down and bought some oxygen. For anyone in the future searching for this question, the answer is:
Yes, the knob won't turn without a bottle attached.
Once I screwed it on, it worked fine.

-Cameron