This Train Control Systems WSK-BAC series WOWKit Complete Sound Conversion Kit for select Bachmann and Bachmann Spectrum steam locomotives is a DCC sound total conversion solution which includes all of the components necessary to convert your engine to WOWSound with a built-in Keep-Alive(TM). This single kit includes decoder, speaker, sound chamber and motherboard - an economical solution it that gives you the assurance that you'll have everything you need for your installation. This WOWKit makes for a simple and easy complete sound conversion so organized and clean the installation yields professional results! Each WOWKit has beautiful installation pictures on the manufacturer website which will guide you confidently through the installation Process.