FITMENT / COMPATIBLE: This switch is used on TOP POST battery DC 12V - 48V only, standard top post battery size: 19 mm cone/tapering positive & 17 mm cone/tapering negative, hook up to TOP post battery NEGATIVE directly. Installation SPACE should be checked to prevent incompatible. | Convenience: direct fit and no modifications, hook up to TOP post battery negative directly, do not need additional battery cables or lugs, isolate and secure the electrical system easily. | Specification: used for DC 12 - 48 V systems, ON/OFF 2 positions, 275 A continuous at DC 12V, 455 A intermittent at DC 12V, 1250 A momentary at DC 12V. | Heavy Duty: ABS plastic housing, durable made for safety use. Extended the top post battery negative to original size: standard top post negative (17 mm cone/tapering negative (-)). | Purpose: Can stand alone or be locked together with another switch. Eliminate any power draw from the battery when vehicle or boat is not in use, disconnects the battery safely, widely used for car, vehicle, Rv and boat.