The Flux Mini is an envelope shaper plug-in by Caelum Audio, they guys that are behind the charming Tape Cassette 2, which is an emulator for the tape cassette era, perfect for a lo-fi house and lo-fi hip hop production. This easy sidechaining and creative modulation platform are free to download for desktop and iOs. It gives you control over the amplitude and has low pass and high pass filters that will definitely add some dynamism and character to your tracks.