Built in Berlin by Maschinenfabrik Raetsch, 1923-1930
The Raetsch family had been in the automotive trade since 1912. In 1922, their company was renamed Sar-Automobil-Gesellschaft mbH.
Late that year their first motorcycles appeared, initially fitted with a Hanfland Kurier engine, and later with a DKW suitable for the tax-exempt class.
1927 Models A 27 (single-speed) and B 27 (3-speed SA) were powered by their own 125cc two-strokes with belt drive and a green enamel tank, and some models were fitted with engines from Kühne.
Their last machine was the 198cc C 200 two-stroke with the engine built in-house. It had a saddle tank, 3-speed gearbox, chain drive and hub brakes.
The marque is covered in some depth by Karl Reese in his book "Berliner Motorräder"
Sources: GTU Oldtimerservice; Motopedia.