Features: It can send PC (program change), CC (control change) and note messages on any channel. - PC messages allows you to change presets. LED of the last pressed PC mode button lights. CC and note messages can be: - toggle (On/Off): It allows you turn functions/effects on and off individually. The LED indicate the state. - momentary: momentary mode allows you to use non-on/off functions like ‘previous/next preset’, ‘tape deck play’, 'tap tempo' etc. It also can be use to turn on an effect for a very short time (I use auto-wah this way). LED lights while you press the button. - impulse: send a MIDI message when you press a button. This mode is great to start/stop and change scenes in Ableton Live. LED of the last pressed impulse mode button lights.