What is the wire gauge or wire cross sectional area for the 9 volt snap connectors?

The wire gauge is a measure of the thickness. In the US, we use American wire gauge or AWG. Elsewhere they use square mm. We have had trouble with a similar product that used #26 AWG wire. This was too thin and it would break at the connection. We would rather have #22 AWG or #24 AWG. Smaller numbers mean thicker wire.