The button on the cord actually works as a controller with 8 different settings. Each time you press it, another function is released. There are 8 fixed settings, starting with 4 different kinds of white light (Warm white, Cool white, Daylight, Dimmed Daylight) followed by 4 kinds of colored light (1 color scenario, multicolored scenario 1, multicolored scenario 2, multicolored scenario 3). The button was added so that this lamp can also be controlled manually without the help of the Calex app.