If you're a music enthusiast or a professional musician, you might want to check out the 909 app by GKRL Labs. It's a free drum sequencer that lets you create beats with a modern interface. The app features drum sounds that imitate the legendary Roland TR-909 Rhythm Composer. One of the best things about this app is that it doesn't require any permissions and there are no ads.

To get started, simply tap a few grid squares and hit play. You can use speakers or headphones for the best sound quality. The app also lets you play along with your beat live and set individual instrument volume levels for great balance. You can mute and solo any instrument and store your beats for playback anytime. Additionally, you can create extended multi-bar beats and choose your beat tempo.

If you have any questions, comments, concerns, or feature requests, you can email the developer. Overall, the 909 app is a great option for anyone looking for a free and easy-to-use drum sequencer app for Android.