[Amps] I need transfer switch information

[ken]

I would like to switch out two circuits from my main panel to an emergency generator with a manual transfer switch or a contactor.  I've sketched out a circuit that will do this even when the main panel is live and I will need a 3PDT switch.

Lots of information on the internet about transfer switches except what's inside the box.  Does anyone know the model number of a transfer switch that is a  3PDT ?

73,
Ken W2DTC