Wall chargers made with gallium nitride (GaN) transistors can be considerably smaller than ones that use silicon instead. An outstanding case in point is the Anker PowerPort Atom III Slim, which is tiny but can still put out 30W to quickly power up an iPad Pro or even a MacBook.

We tested this svelte USB-C battery charger in the field. Read on to see how well it lives up to its promise.

Anker PowerPort Atom III Slim review

The length and width of this charger are smaller than a credit card, though it’s thicker, of course. The PowerPort Atom III Slim is 3.0 inches by 1.75 in. by 0.6 in., and as mere 2.1 ounces (0.13 pounds).

The rival Apple 30W charger is much, much larger: 4 inches by 4 in. by 1.5 in. That’s the disadvantage of using silicon instead of GaN.

All the edges and corners of Anker’s offering are rounded. It comes only in black, with a plastic casing that has a very fine texture.

The USB-C port is on one of the short edges. Near it is a blue LED that lights up when power is available.

The PowerPort Atom III Slim is very pocketable, especially as the integrated AC power prongs fold down. Or it takes up almost no room in a backpack, bag or purse.

Anker PowerPort Atom III Slim performance

The standard 2018 iPad Pro wall charger offers 18W, but this tablet can take in 30W. That makes it well suited for the PowerPort Atom III Slim.

When we tested Anker’s charger with a 12.9-inch iPad Pro, the battery level went up 20% in 20 minutes of charging. That’s in-line with other 30W chargers we’ve tested this tablet with.

For comparison, Apple’s 18W offering that comes bundled with this slate increased the battery level 12% in the same time period.

The PowerPort Atom III Slim can also be used to charge an iPhone, with the addition of a Lighting-to-USB-C cable. In our tests, the starting battery level has a tremendous influence on how quickly the handset charges, likely because Apple wants to be very sure the battery isn’t overcharged. When our test iPhone XS Max was below 20% at the start of the test, it could go up over 30% in 20 minutes of charging. With the starting battery level between 20% and 70%, the level increased about 25% in 20 minutes. When the battery level gets above 70%, charging slows considerably.

Anker PowerPort Atom III Slim final thoughts

No one wants to carry around more than is necessary, and the PowerPort Atom III Slim really lives up to its name. It’s so much smaller than Apple’s offering that it’s a brilliant demonstration that gallium nitride transistors are a better option for chargers than silicon ones.

Beyond the sleek shape, our tests show this charger provides all the power it promises.

Pricing

The Anker PowerPort Atom III Slim is $34.99.

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Comparable products

Apple makes its own 30W USB-C Power Adapter. This is $49, and as mentioned earlier is considerably larger than Anker’s.

The RavPower PD Pioneer 45W isn’t quite as small as Anker’s, but it’s close. It offers 45W, but iPads can’t take advantage of that extra power. It sells for $29.99.

Anker provided Cult of Mac with a review unit for this article. See our reviews policy, and check out more in-depth reviews of Apple-related items.