The HD system allows the user to select independent illumination colors for the gauge readings and needles, as well as the message centers. Calibration and personal settings are manipulated with the built-in, capacitive-touch buttons, or the available Bluetooth app for Apple and Android devices. Each needle hub is black nickel plated spun-aluminum to match the buttons. All HDX instrument systems feature dead-faced indicators (turn signals, high beam, check engine, cruise control, parking brake, plus two user-definable), and a red, settable warning light for each gauge. With their central control box, installation is greatly simplified with vehicle-harness sourced signals and supplied, solid state sending units connecting cleanly to their respective terminal.