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Despite what you might think from watching “Law and Order,” it’s not only crooks who want disposable phone numbers.

There are all kinds of reasons people don’t want to give out their number, in part accounting for the popularity of cheap cellphones, often called “burners.”

But it’s not really the cellphone most people want to replace. It’s just the number.

So one startup has built its business around letting people use their cellphone with multiple “burner” phone numbers.

Ad Hoc labs, a nine-person, Los Angeles-based startup, created Burner, an iOS and Android app that lets people get one or more temporary numbers. The app is free to download, but customers pay for more than a minimal amount of use or for more than one burner number.

And it’s built a pretty good business, with Burner frequently ranking near the top of the best-grossing apps in the utilities section of Apple’s App Store.

Ad Hoc won’t say how much that means in annual revenue, but the company did say it is approaching a million downloads for its flagship app. “We are in the top couple hundred of all grossing apps,” CEO Greg Cohn told Re/code. “We are doing very well.”

On Thursday the company is adding a few new tricks, most notably the ability to send picture and video messages. Prior versions could make calls and send text messages, but not handle multimedia messages. It’s also adding a desktop plug-in for the Chrome browser that makes it easier to remember one’s Burner number when filling out online forms.

The updates are available initially for the iPhone version, with an update planned for the Android version in the coming months.

Burner is also extending its usual free trial period, giving new iOS users a year of limited use. It’s not giving a ton of minutes or texts for free, but Cohn said it is enough for casual use and for a more serious user to see the value of the paid service.