A B switch used to switch relays between 2 banks of batteries.  Using this switch with 2 relays allows you to manually switch your MPPT or your Inverter between battery banks as you need.

A double-pole single-throw (DPST)on-on panel mount power Rocker Switch.
19.4 x 22.2mm Panel cut-out
Easy snap-in mounting
50mR Maximum contact resistance
100MR Minimum insulation resistance

Contact Configuration: DPDT 
Switch Operation: On-On 
Actuator / Cap Colour: Black 
Switch Mounting: Panel 
Contact Current Max: 10A