Cartesian Product is Small iff Inverse is Small

Theorem
Let $A$ and $B$ be classes.

Then the Cartesian product $\left({ A \times B }\right)$ is a small class iff $\left({ B \times A }\right)$ is small.

Proof
If $\left({ B \times A }\right)$ is a small class, then $\left({ A \times B }\right)$ is also small by Inverse is Small.

Similarly, if $\left({ A \times B }\right)$ is small, then $\left({ B \times A }\right)$ by the same statement above.