Portable transformer plugs are characterized by the following:

Compact size: These plugs are designed to be portable and easy to carry, which makes them convenient for use while traveling or on the go.

Multiple voltage output: Portable transformer plugs are capable of converting the voltage of an electrical outlet to a different voltage, which can be useful for powering devices that are not compatible with the local power grid.

Multiple plug options: Many portable transformer plugs come with a variety of plug options, allowing them to be used in different countries with different electrical outlets.

Surge protection: Some portable transformer plugs include surge protection, which can help to protect connected devices from power surges and voltage fluctuations.

Multiple outlets: Many portable transformer plugs have multiple outlets, allowing multiple devices to be powered at the same time.

LED display: Some portable transformer plugs have an LED display that shows the current output voltage and other information, which can be useful for ensuring that devices are receiving the correct power.