The release notes for the latest Kindle software update that launched a few weeks ago were vague, but some users have discovered a useful feature for anyone with cheaper ad-supported e-readers. In addition to more robust line and text spacing options, you now have the option to filter ads that “may not be appropriate for everyone” so they don’t show up on the Kindle’s lockscreen and homescreen, as spotted by The eBook Reader.

It’s part of the 5.18.3 software update for the Kindle Scribes, Kindle Colorsoft, and 11th and 12th generation versions of the basic Kindle and Paperwhite, which adds two new lockscreen ad options accessible in the “Your Account” section of the Kindle’s settings.

Opting for an ad-supported version of a Kindle can save you $20, but previously, you didn’t have any options to customize what types of ads you see. Although they can feature everything from cars to beauty products, the ads frequently feature books and are often based on your own personal browsing and reading habits. If you happen to read a lot of steamy romance novels with cover art that’s inappropriate for younger readers, you could be served ads for similar titles.

You can now turn off “Personalized Ads” so that the ads you see will no longer be based on your browsing or purchase history, and turn on “Filter ads,” which will hide inappropriate content. It will still be up to Amazon to decide what the company considers appropriate versus inappropriate ad content. If you’ve turned on ad filtering and are still seeing ads you’d rather not have showing up on your Kindle’s lockscreen, you’ll need to visit Amazon’s website and pay $20 to have the ads removed from your e-reader entirely.