KP04 Illuminated Surface Mount Pushbuttons NKK Switches KP04 Illuminated Surface Mount Pushbuttons are SPST momentary switches with RGB and RGBW illumination options. These switches feature several configuration options, including tactile and nontactile variations, and a variety of cap sizes and types. NKK Switches KP04 Illuminated Surface Mount Pushbuttons are optimized for surface mount reflow soldering, and feature momentary, normally open switching with a stroke of 3.5mm.