This QuickCar Extreme Series gauge measures water pressure. Designed for 12-volt or 16-volt power systems, this 2-5/8" gauge has a 0-100 PSI display range with a white face, bright red pointer needle, and LED lighting. QuickCar Extreme gauges are top of the line mechanical gauges that feature an internal warning light system where the ENTIRE 2-5/8" face of the gauge will change color when a problem occurs. Comes with a male 1/8"NPT connection on the backside so it is universal for most cars. Pressure Line Kit and 4 PSI oil pressure switch (PPM889-3021)(required for warning function) are not included and are both sold separately.