First, we need to point out that the USB-C cable is only one part of the fast charging equation. The AC adapter—or “charging brick”—also needs to support fast charging. A fast-charging compatible cable won’t charge your device faster than if you’re using a standard AC adapter.

If your phone supports one of the several fast charging standards, it probably came with an AC adapter and cable that enables it. If not, you can check which fast charging standard your device supports and find compatible accessories. Check out our guide to the best phone chargers for a variety of options.

There are a couple of things you can do to check if your existing cables support fast charging. First, you should start by checking the packaging of your phone or find the listing online and see what it says is included in the box.

If your phone came with a fast-charging USB-C cable, the specs of the cable will be listed on the box or online. Sometimes it will simply say “Fast Charging.” Other terms to look for are “Adaptive Fast Charging,” “Quick Charge,” and “USB PD” or “USB Power Delivery.”

Another easy thing to check is the thickness of the cable. Fast-charging cables tend to be a bit thicker than regular cables, but this isn’t always super noticeable.

If you know the AC adapter supports fast charging, you can use your phone to make sure the cable is fast charging too. iPhone and Android can use an app called Ampere to see a real-time measurement of voltage. Look for 5V, 9V, 12V, or higher. Some Android phones will also put “Fast Charging” on the lock screen (shown below).

Sadly, most USB-C cables don’t have fast charging labels on the cable itself. However, you may see one that has a lightning bolt icon or initials for “Quick Charge.”

In general, it’s a good rule of thumb to stick with USB-C cables and adapters that are made specifically for your phone. In most cases, that will ensure you’re getting the fastest speeds possible. Not all USB-C cables are created equal, so be careful with what you use.