Bernard
I don't know the mechanics of 'air trap'. If you can tell me what to look for, will do so. if you are talking controlled bubble, it is not that. there is an optic effect, but there is no bubbles. they are all uniformly shaped. they can be felt on both insides and outsides. there is honest wear on the base. the glass does not seem to be cased at the top rim or the foot. I can't tell on the blue ball connector knob.
regards
Dave