DCC Concepts DCP-ADX Cobalt Alpha Extension DisplayCobalt Alpha Extension Display The Cobalt ‘± Alpha main unit has a digital display that repeats commands and displays the accessory number that has been operated.We knew that modellers will want to have an extension display visible on their control panel so we created this economical and easy to use accessory.Supplied with an attractive milled and anodised aluminium surround for neat and tidy installation, the Alpha Extension display simply plugs directly on to the Cobalt Alpha unit.The Cobalt Alpha extension display is simple to install.How does the Cobalt ‘± Alpha system work? Cobalt Alpha Range Booklet