OPERATION: This car battery isolator switch is used for DC 12V 24V systems, On/Off 2 position, Max Withstand Current: 12V 150A. Recommended to mount on the NEGATIVE battery terminal. PROTECTIVE COVER: The battery main cut off switch comes with a waterproof protective cap, which can better protect dust and water entering the key hole. NO MORE BATTERY DRAIN: The battery cut off isolator switches help isolate and secure the electrical system, eliminate any electrical consumption from the battery when the vehicle or boat is not in use, safely disconnect the battery 2 * PORTABLE KEYS: The key can be removed when there is no electrical connection. PACKAGE INCLUDES: 1 x Battery Disconnect Switch, 2 x Keys, 1 x Waterproof Cover. Size: 2 Brass Terminals: 5/16