tinted yellow Amber-coloured retroreflective markers on the front turn signal indicators which double as night illumination Red-coloured retroreflective markers at side edge of taillamps Location of ID-tag on A-pillar Emission control device for petrol engines only Radio with different frequency steps when tuning to different radio stations 85 mph maximum speedometer with 55 mph prominently marked Tinted glass band across the top of front windscreen If passenger side external rear view mirror is included, the mirror must carry the warning: "Vehicles are closer than they appear" Equipment and features The standard and optional features are numerous along with a large number of engine and gearbox options. Customers could choose cloth, MB-Tex vinyl, velour or leather for the upholstery as well as interior wood trim for dashboard and centre console. The paint and interior colour palettes are extensive as well. The driving dynamic enhancement options for extra cost became more extensive over the time: ABS (from August 1980 onward), self-locking differential gear, five-speed manual gearbox (introduced in 1982 for European markets only), Tempomat cruise control system, power steering system (standard from 1982 onward), passenger-side external rear view mirror (standard on S123 model), "Alpine" horn with selectable loudness (popular in Switzerland due to strict noise regulations), retractable steering column (from 1982 onward) and so forth. The extra cost options for creature comforts includes power windows (with a cut-off switch for the rear passenger door windows), vacuum-powered central locking system, sunroof (manual and electric), air conditioning system (manual or automatic control), seats with orthopaedic support, electrically heated seats (all seats were individually ordered), pre-heating system (for heating the passenger compartment at a pre-selected time when the engine is not running), an assortment of different radios with and without cassette players, rear seat head rests, etc. The W123s destined for the North American market tended to have more features as standard, reflecting the American customer's preference for luxury accessories. For the first time in an executive saloon from Mercedes-Benz, the W123 had the option of fully automatic climate control at extra cost. This option was popular in the North American and Japanese markets. A rare option was a column gear selector that could be ordered with an automatic gearbox if the customer wished. The most expensive option was the Becker radio telephone, selling for 13,512 Deutsche Mark. In the estate/station wagon model, a third row rear-facing foldable seat was offered as an extra cost