Complex needs to judged

If $z_1$ and $z_2$ are two complex natural numbers such that

$| z_1 | < 1 < | z_2 |,$

then what can we say about the value of

$\left | \frac{ 1 - z_1 \bar{ z_2} } { z_2 - z_2} \right|$

(Calvin edit: It is not clear what "complex natural numbers" means. I believe that is should just be "complex numbers".)