The Quartz Hobbs Meter is a great addition to any home cockpit.  This unit is for DIY Hobbs products. We currently use these in our full simulator builds and hard wire the unit into the Master Switch or the magneto. The master switch is typically done with a relay. The relay is tripped when the master battery is turned on, which opens a separate circuit for the Hobbs meter. You will need an 8 - 12V power supply to power this Hobbs meter.