Blue Sea Systems analog meters have a modern, "flat scale" design which makes precise reading easy. Simple two-wire connection. Display 2.625" W, 1.26" H. Can also be mounted in a 2-1/16" hole using the studs on the back of the case. Ammeters measure alternator output, battery charger output, distribution panel consumption, inverter consumption or solar panel array output. Meters are accurate to ±3% full scale.