The author remixed this model.
as mentioned above, made to be longer to fit a step down converter and give ample space for the rocker switch, amazon links below:
rocker switch - https://www.amazon.com/dp/B07KS2TQ45?psc=1&ref=ppx_yo2ov_dt_b_product_details
12V 30A Regulated Switching PSU - https://www.amazon.com/dp/B06XJVYDDW?psc=1&ref=ppx_yo2ov_dt_b_product_details