They are called "I-Bus", "Nautilus" or "OBI-Bus"; and every Citaro rigid bus is one of a kind. Where one of them will remind you of a cool Apple Store in white, mint green and with a wooden floor look, another will catch your eye with its stainless steel inserts and orange colour scheme. A special lighting concept has been developed for each vehicle. "Torches" on the side walls can bathe the vehicle interior in a pleasantly warm and calming light, or in a cool, refreshing light. The LED lighting in the "Nautilus" is the master touch, rounding off the vehicle's maritime flair in an ideal way. For blue is most certainly the order of the day here: the Citaro's side walls were printed using a special technique with marine motifs. The sprayed-on floor covering was coloured blue; and even the fabric for the doubly-upholstered ISE seats has a pebble stone pattern which goes well with it. The head sections in blue round it all off. In addition there are information and entertainment media deployed in all vehicles, allowing route information, advertising and news headlines to be displayed around the clock.
Each Citaro has two standing areas. Standing area number one has been laid out for wheelchair use and is on the right in the direction of travel directly in front of door number two. The fitting of a pivot-and-slide door provides additional room, which Spillmann has made use of in the specification. A single fold-down seat and a rest support which doubles up as a fold-down seat for mother and child complete the wheelchair area. The second standing area is located directly opposite door number two and has similar features, but with a "trident" handrail design in the centre, which offers support to the front, rear and to the sides. As in the "Nautilus", all Citaros are fitted with the comfortable, double-upholstered ISE country bus seating.