Series 6425 Pushbutton Key Switches Marquardt Series 6425 Pushbutton Key Switches are single pole switches available with optional yellow, green, or red LED. This series is rated to 100mA / 28V and offer a wide range of key caps for flexible design options. Marquardt Series 6425 Pushbutton Key Switches feature pleasant actuation characteristics, low actuation noise, and low bounce time.