About a week ago, Opera teased its new Max data-savings app for Android and allowed users to pre-register. Starting today, Opera will roll out Max to these pre-registered Android users in the U.S. on a first-come, first-served bases. Pre-registered European users can also install it today (there doesn’t seem to be a cap for them).

Opera Max effectively takes the compression technology the company developed to power its Opera Mini mobile browser and the “turbo” mode in its desktop apps and extends it to all of Android. The app sets up a VPN connection to Opera on your phone that is activated every time you switch from your home WiFi network to the cell network. All your non-encrypted data is then routed through Opera’s servers and compressed there.

If you’re on a metered plan, having Opera compress most of the images, videos and text you pull in over the cell network sounds like a great idea, as long as you are okay with the potential privacy tradeoff of having all your data go through Opera’s networks.

I’ve been testing the app for the last week and it’s a pretty seamless experience. You install it once and just forget about it from then on. It just works.

I did not notice any major increase in lag when using the app and Opera seems to be pretty conservative when it comes to image compression, because I’m having a hard time finding any compression artifacts.

You can always go back into the app and turn it off, but I’ve never quite felt the need to do so. Otherwise, the Max app just sits in the background and keeps track of your data usage.

Opera says if you are a heavy Flipboard, Vine and Instagram user, you can expect to save about 50 percent of your bandwidth by using Max. Based on my experience, that sounds about right. My savings in Instagram were actually quite a bit higher than 50 percent without any noticeable decline in image quality because of the compression.

If you are mostly surfing the web when you are out and about, though, you may not see any major differences (unless you spend most of your time on very image-heavy sites). Of course, if you are mostly in the Facebook app or email, chances are you are on an encrypted connection, so all your traffic will bypass Opera’s servers anyway. In daily use, my savings averaged out somewhere between 25 and 35 percent.

Still, Max can definitely help you get more mileage out of your mobile plans and may be especially useful if you are travelling internationally and only have a relatively small data allowance.

One thing Opera didn’t quite clarify in its teaser, though, is that Max doesn’t quite come for free. During the beta period, Max will remain free. You may see the “days of savings left” meter in the app and you will have to go into the app to charge up for another week for free. After the beta period ends, though, Opera plans to give users the option to either see one ad per day of savings or to pay $1 per month. That seems like a pretty fair price and if you are on a metered plan, that $1 may just pay for itself.