BLUE SEA SYSTEMS also offers an AC Digital Frequency Meter (Model #8239) that measures frequency up to 90Hz in 0.1 Hz increments. And Model #8247, a Digital AC Multimeter with alarm, combines the ability to read amperage, voltage, watts and frequency with programmable visual/audible alarms for high and low amperage. This multimeter also features a sleep mode that blanks the display for power conservation. Accuracy of voltage and amperage readings with BLUE SEA SYSTEMS' digital AC meters is greater than 1.5%; frequency readings are accurate to greater than 0.1%. Each of these versatile displays features a rugged splash-proof front and is designed for surface mounting in a standard two-inch hole or rear mounting in any standard BLUE SEA SYSTEMS distribution panel meter opening. Each display also features three brightness levels for optimum visibility under a variety of conditions. In addition, each of the 8200 Series Digital Meters is designed to easily replace existing analog meters in BLUE SEA SYSTEMS' panels.