After going through beta testing since 2013, Google's new Gmail ad format is now available for advertisers looking to purchase space as of Tuesday, according to Tech Crunch. These native ads are located at the top of the inbox in Gmail and are available for purchase through AdWords.

Google has been testing this ad format for the past couple of years by allowing them to be used by a select group of advertisers, according to Beta News. With the benefits now clear, they're ready to allow other companies to jump on board and start their email campaigns.

Beta testing revealed that fewer, but higher quality, ads are the best format and achieve the most amount of integration into the Gmail inbox experience and help to "recreate the informational and visual richness of a landing page."

Each ad can be forwarded or saved to your inbox, meaning you can treat them much like a standard email. Google only charges advertisers on the first click on the ad unit - all clicks afterwards are free.

Google has stated that users will have control over the type of ads that they see and can even opt out of internet-based ads, giving plenty of flexibility over your inbox experience, according to Invest Correctly.

The launch comes at the same time as Google's new logo redesign, which was the first one since 1999.