Alongside its new iPhone 17 lineup, Apple casually launched a world’s first last week inside the very dull sounding “Apple 40W Dynamic Power Adapter with 60W Max.” It’s the first charger to support the USB PD 3.2 AVS protocol, giving you some of the benefits of a more powerful 60W charger in a compact 40W package.

AVS — which stands for Adjustable Voltage Supply — provides granular voltage options allowing the power source to offer more precise and efficient charging of devices like smartphones and laptops. You can see it listed on the charger specs from Apple Insider’s hands-on.

For reasons of safety, efficiency, and longevity, the batteries in our phones and laptops do not charge at their maximum possible input for the entirety of the charging cycle. Instead it’s regulated at predefined voltages to slow down charging as the battery fills. With AVS, the power source can provide a very specific voltage that is closer to the ideal needed for the device being charged, speeding up charging in the process.

However, unlike a true 60W charger, Apple’s little 40W GaN charger can not maintain that peak 60W rate forever — only 18 minutes as demonstrated by Privaterbok over at the r/UsbCHardware subreddit. That makes it suitable for fast charging a new iPhone 17 but not a MacBook Pro, which is why Apple sells it as a 40W charger “with 60W Max” and not a 60W charger.

It also means that you’ll likely need Apple’s $39 Dynamic Power Adapter if you want to match Apple’s fast charging claim for the iPhone 17 models (“up to 50 percent in 20 minutes”) or wait for Anker and others to provide a compatible USB PD 3.2 AVS charger of their own.