Which breaker for sub amp?

[ZachD]

I currently have an aftermarket 12in sub connected directly to one of the two batteries in my boat. That said, I want to connect it to the panel circuit breaker in ACCY spot so that I can switch which battery is powering it. I wanted to ask if anyone could help me know which amp breaker to purchase here for the setup I have. The amp is an MTX 421D and the specs are listed here. Candidly, I don't know much about this so any advice on what to do once I purchase the breaker is appreciated. I assume I can take the same wire that is currently directly connected to the battery and wire it into the breaker (what amp #) on the panel box...? thanks!

I believe this is the only part I need : http://www.nautiqueparts.com/product...rs-pcm-engine/

Specs of the amp I am hooking up here under DETAILS tab: https://www.crutchfield.com/S-9fksyl...under421D.html

[swatguy]

Just fake the positive right now going from your battery to your amp and run that to you perko switch main positive post instead of going to the battery......... .Viola