Apple’s new iPhone 11 Pro and 11 Pro Max are oddities in a way for the technology company: they’re bigger, heavier, and thicker than last year’s models, bucking the usual trend where Apple tries to release increasingly thinner and lighter phones. Not coincidentally, the new heftier iPhones also promise markedly better battery life than the iPhone XS and XS Max: four hours better on the smaller phone, and five hours better on the larger one.

For years, people have asked why companies won’t just make phones a little bigger and heavier in order to offer better battery life. And with the iPhone 11 Pro lineup, it looks like Apple is finally taking note.

Bigger, heavier, and better battery life

To put the jump in battery in perspective, the last few upgrades for Apple were the iPhone 7 (two hours better battery life than the 6S), the iPhone X (two hours better than the iPhone 7), and the XS and the XS Max (30 minutes and one hour and 30 minutes longer than the X, respectively, due to software and hardware improvements in power efficiency). Instead of making another pitiful attempt at bumping battery life like the XS, Apple is offering twice its best battery life update in a form factor that’s nearly the same size as the XS line.

It’s a move we’ve seen before, though: last year’s XS phones paled in comparison to the iPhone XR, which might be the longest-lasting phone Apple’s ever made. How? Because Apple made the decision to sell a bigger and heavier phone — with a bigger battery — that combined the same efficiency improvements that Apple made on the XS phones.

Improved efficiency plus a bigger battery is apparently a winning formula for great battery life, and with the iPhone 11 Pro models, it looks like Apple is applying that lesson in reverse. The new 11 Pro phones are nearly as thick and heavy as the standard 11 — the smaller iPhone 11 Pro is 6.67 percent thicker and nearly half an ounce heavier than the XS — presumably due to Apple adding beefier batteries in the new models.

We likely won’t know for sure how big the batteries in the new iPhones are until someone tears one apart, and, presumably, the numbers still won’t compare to something like Samsung’s Galaxy S10 and Note phones, which top out at 4,500mAh batteries that are almost guaranteed to be vastly larger than whatever Apple is offering. And that’s to say nothing of the (sadly unfunded) 18,000mAh monster that Energizer wanted to make. But any improvement here is a welcome one, especially if the battery claims hold up.

The battery is just part of the story

Apple says that improving the batteries themselves is only part of the story: the company also highlights that the new displays in the 11 Pro are “up to 15 percent more power efficient,” and that iOS 13 itself is designed to more efficiently run on the new phones. There’s also a new custom-designed power management unit (PMU) that Apple says is key to offering the improved battery life. But as we saw last year with the XS phones, that kind of upgrade can only get things so far. At a certain point, it does come down to how big the battery is.

Apple has historically pursued thinness with an aggressive mindset over the past decade. Its phones have gotten slimmer at the expense of battery life and protruding camera modules, and its laptops are thinner at the price of ports and a problematic keyboard. With the iPhone 11 Pro and Pro Max, it looks like that trend is finally reversing by prioritizing function over form.

Correction: The iPhone 11 Pro is 0.02 inches thicker than the iPhone XS, not a quarter-inch as this post originally wrote.