Use the traffic light colours for the selection of units and accessories:

The colour of the traffic light shows, already when starting to design the unit, important information concerning the appropriateness of the unit. When pre-selecting the accessories, the traffic light gives a feedback signal, thus indicating which series are equipped with the required accessories. Additionally you obtain the price including the accessories in the hit list, this will help you to find the most convenient solution quickly and reliably.

         
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