The more USB ports on a device, the better, but things can get confusing when they all have a different symbol on them. Among the markings seen next to USB ports, it’s not uncommon to see a battery icon, which typically indicates that it’s a USB Power Delivery port. Known as USB PD for short, this port means it can deliver higher power levels than a typical USB port, but can also charge connected devices.

The USB PD charging protocol has a long history and was first introduced in 2012, meaning it predates the debut of the USB-C port. However, USB PD was updated in 2021 and is now able to deliver up to 240W of power, meaning it can support more demanding devices like high-end laptops or some monitors. Beyond supplying more power, the USB PD port has some cool use cases that you might not know about.

When you see a battery symbol next to a USB port, it can mean a few things. Most commonly, the icon means that port is USB PD compatible and can offer a more sophisticated charging protocol. Using USB PD, you can charge your laptop faster since Power Delivery conducts an intelligent digital handshake between device and charger that provides the right amount of voltage and current without the risk of overheating.

The battery symbol could also translate to another useful feature in the form of bidirectional charging. When looking at your laptop’s USB ports, you can use the one with a battery symbol to charge another device, like your smartphone or AirPods. Even further, some laptops’ USB ports with this symbol can charge a device even when it’s asleep or shut down thanks to “Always On” charging. Keep in mind that leaving your smartphone plugged into your laptop’s compatible port can completely drain the battery. Luckily, most laptop makers have included a way to disable this charging feature.

As much sense as a battery icon makes, USB PD has somewhat of an identity crisis when it comes to the symbol that represents it. According to the USB Implementers Forum, the nonprofit corporation that created and set the official USB standards, the official symbol is a battery shape made with negative space.

USB Implementers Forum

Members of the USB Implementers Forum include Apple, Microsoft and HP, but not all companies align with how they indicate that a USB port is equipped with the Power Delivery charging protocol. Across devices, there can be the official battery symbol from the USB Implementers Forum, a different battery logo, a lightning bolt (not to be confused with the Thunderbolt symbol) or even simply the letters “PD” to indicate that it’s a USB PD port. On top of that, some companies will have USB ports that are compatible with the USB PD protocol but don’t indicate it, like Apple’s Thunderbolt ports for its MacBooks. If in doubt, it’s best to check the manufacturer’s specifications in a user manual.