Universal voltmeter ammeter USB tester. A meter designed for a USB port that simultaneously measures voltage and current. The meter is connected in series between the USB port of the charger or computer and the receiver, for example. phone, external drive, USB lamp, etc. The meter has one USB input and output. Product Features: - voltage measurement range: 4 - 20Vdc | accuracy +/-1% - USB current consumption ammeter - current measurement range: 0.02 - 3A dc | accuracy +/-1% - male and female USB connector - Plug&Play - no drivers required - external dimensions: 72mm x 23mm