Blue Sea 6011200 m-Series Battery Switch Dual Circuit Plus - Black 
m-Series Mini Dual Circuit Plus Battery Switch - Black
Simultaneously switches two isolated battery banks or combines battery banks to all loads.
Make before break contact design allows switching between battery banks without power interruption.
Switch Type: tDual Circuit Plus Color:tBlack Switch Positions:t3 Battery Combine:tYes Alternator Field Disconnect: tNo Maximum Voltage:t32V DC Continuous Rating :t300A Intermittent Rating :t450A (5 min) Cranking Rating 10 sec: t1000A Cranking Rating 1 min: t650A Battery Inputs:t2 Cable Clearance For 4/0 AWG Cables:t1.12in (28.45 mm) Cable Size to Meet Ratings:t4/0 AWG (120mm²) Mounting Holes: tAccept #10 Screw Terminal Stud Size:t3/8"-16 (M10) Terminal Stud Torque:t120 in-lb (13.56 Nm) Weight:t0.80lb (0.36 kg)
WARNING: This product can expose you to chemicals including di(2-ethylhexyl)phthalate (dehp) which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.