This is because the air gap will eventually become too large for the magnetic field to overcome.

Even in this case, there is no ability for computers on opposite sides of the air gap to communicate.

In this case the maximum possible air gap is only 0.5 to 0.8 mm.

Category 5 requires an air gap, not merely a valve.

Back siphonage may be prevented by use of an air gap.

However most air gaps also limit the system pressure that may be transmitted across them.

The air gap is very important for the function of this device.

In this on position the field is effectively passing across an air gap (at the base and top).

A little goes a long way since you're only trying to eliminate air gaps, not frost a cake.

I can almost guarantee that the systems were specified with an 'air gap' for security.