Perko Dual Battery Selector Switch - Cup Mount One Size. This switch provides the flexibility of selection between batteries or combined operation of both batteries in parallel for starting or charging. It can also serve as an emergency main disconnect switch in the event of an electrical problem. All models are ignition protected. The cup mount option creates an attractive durable easy open/close cover and protects the switch face. An installation hole size of 4" is required for cup mount installation. Features/Specifications: Rating: 140 Amps Continuous 200 Amps 5 Min. Intermittent 250 Amps 30 Second Start Cup Mount Installation Hole Size: 4" Cup Diameter Size: 4-1/2" Face Dimensions: 3-7/8" x 3-1/4" For use with alternators and generators 6-50 V.D.C. marine electrical systems Specifications for Perko Dual Battery Selector Switch: Manufacturer: Perko Color: Black Features of Perko Dual Battery Selector Switch For two or more batteries Unique oval shape mounts in a round hole Removable actuator key Package Contents: Perko Dual Battery Selector Switch Perko 8521DPC: Dual Battery Selector Switch - Cup Mount One Size