Mercedes-Benz Citaro Hybrid (former SG4004B) at a workshop in the United Kingdom [Photo: Allan Hollis] Mercedes-Benz Citaro Hybrid (former SG4004B) at a workshop in the United Kingdom [Photo: Allan Hollis] Mercedes-Benz Citaro Hybrid (former SG4004B) at a workshop in the United Kingdom [Photo: Allan Hollis]