YouTube will finally debut a music streaming service that won't include video, just audio. Now, details about YouTube's "Music Key" streaming service are being leaked.

Ad-free streaming music will be offered from Music Key. It will cost $9.99 per month which is similar to what Spotify, Slacker and Rdio offer.

Android Police released more details on what they believe will be offered from the streaming music service.

Android Police believe that the $9.99 fee for Music Key will also give users access to Google Play All Access. Google Play All Access is very similar to Spotify and it offers unlimited ad-free music.

Those who currently use Google Play All Access could receive a discounted rate to Music Key, but that isn't confirmed yet.

The proposed YouTube streaming music service has been rumored since March 2013, but it hasn't made much progress. Two executives left the division of YouTube recently, according to the Wall Street Journal, likely due to arguments over the service.

Android Police added that documents show that Google has already added more than 20 million high-quality tracks and albums to the Music Key's planned library.

Google has reportedly reserved the website YouTubeMusicKey.com for the service, Android Police adds. It's unclear when this service will finally debut.

If rumors are proven true, MusicKey will also offer access to concert footage, covers and remixes. It will also provide recommendations based on your listening history.

The non-traditional versions of songs that many artists don't release or aren't usually easily accessible will be available on MusicKey. This will help differentiate MusicKey from its competitors.

Will you signup for MusicKey at $9.99 per month? Which streaming music service do you use? Do you use the free version with ads or the ad-free paid version? Leave us a comment below in the comments section and let us know.