Calibrated to measure 17 different refrigerants (R12, R22, R123, R124, R134a, R401A, R401B, R402A, R402B, R404A, R407C, R408A, R409A, R410A, R502, R507, R508B) these accurate gauges allow you to choose the temperature (°F or °C) and pressure units (PSI, bar, kPa and kg/cm3) your most comfortable using. The low side gauge has a pressure scale of 30 inHg VAC to 250 psig and the high side gauge has a pressure scale of 0 to 800 psig. Gauges come with a backlight to enhance the view and make the gauges easy to see in low light conditions.Automatic shutdown after 15 minutes of inactivity. Low battery indicator. Hoses NOT included.