Now maybe they changed things with the 126 chassis, but my '80 300SD has 2 different size blades. The shortest being 18" and is the one that sweeps in front of the driver. The other is 19". To make things even more confusing, the wiper arm for the 19" blade is shorter than the 18" wiper blade. My car has original stainless steel Bosch "blades", the part that holds the rubber element. Since these aren't just available anywhere, I replace just the rubber element/refill with Bosch "Microedge" refills. Since the 126 cars have the same "flopping" wiper pattern, I would venture to guess that the wiper dimensions may be the same.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member