Face unlock on the Pixel 4 just gained an important security feature you need to turn on

While Face Unlock on the Pixel 4 is definitely an improvement over both physical and in-display fingerprint scanners, Google's 3D face scanning biometric isn't all it could be. For one, it has limited app support, but even for simple unlocking, there's a flaw that could allow someone to unlock your phone without your permission. A new feature rolling out as part of the April Security Update fixes that.

Once the update hits your phone this week, a new toggle will appear inside the Face Unlock tab in the Device Security settings. It's called "Require eyes to be open," and as the name suggests, it won't unlock your phone unless your eyes are open. That means if you're sleeping someone can't get into your phone and if you just want to keep someone out, all you need to do is close your eyes.

Here's how to turn it on:

It's an important security feature that Apple has had on the iPhone since Face ID arrived, and while six months is a long time to wait for the Pixel 4 to get it, we're glad it's here. I tested it a few times on my Pixel 4 and it worked very well, with my phone simply refusing to unlock when my eyes were closed. And that's with heavily tinted glasses, so Google has designed a strong system here.

One more tip: If you want to completely disable Face Unlock temporarily, you can hold down the power button for a second and tap the Lockdown button at the bottom. That will immediately lock your phone and force a PIN in order to unlock it. After an unlock it will go back to normal.