Gear Best is selling the USB Detector Current Voltage Tester for $4.59, down from $8.30, a 45 percent discount. The device is a handy tool for users who own multiple USB peripherals like external hard drives and pen drives, allowing them to measure the USB voltage of a device to prevent damage through use of something  with incompatible voltage.

The UBS Detector Current Voltage Tester on Gear Best supports USB 2.0 and USB 3.0. The device comes with a single USB connector that can be used to connect it to any device like a PC or laptop. It is also enabled with two out USB connectors on which other USB devices like smartphones or gaming consoles can be connected.

It can detect voltage no load and overload states and it works without a power supply, supporting direct current voltage measurement in the range of 3-9 volts and 0-5 amps. It weighs only 90 grams.

Geek Snack called the 90-gram (3.2 ounce) unit a future-proof gadget because it can work with USB Type-C devices.

The USB voltage tester is only available in black. Gear Best is offering worldwide free shipping and promises to deliver in 3-5 business days.