SOS were motorcycles produced from 1927 to 1939. Len Vale-Onslow first built the machines at Hallow, near Worcester, before transferring manufacture to Birmingham, and eventually passing control of the firm to Tommy Meeten.
- 1927 Due to the lack of a gas supply at Hallow, the first machines were made using electric welding for the frames. The motorcycles were variously referrd to as Super Onslow Special or So Obviously Superior. Most had Villiers engines, but some of the early machines had JAP.
- 1930 The last of the JAP engines to be used were 250cc and 350cc ohv models. From then on it was Villiers units ranging between 172cc and 343cc. All the models were well made and well finished.
- 1932 Manufacture transferred to Birmingham.
- 1933 The first of the water-cooled models appeared, based on 148cc and 172cc Villiers engines fitted with an SOS top half plus a suitable radiator. Later in the year a 249cc water-cooled model was added. Control of the firm the passed to Tommy Meeten.
- 1934 The range expanded, models were given names and air- or water-cooled machines were offered to various specifications with engine capacities ranging between 172cc and 346cc. All-weather models offered deep-valenced mudguards, leg shields and under-shields.
- 1936 Meetens Motor Mecca was opened on the Kingston bypass where the supply of SOS continued as well finished, high quality machines.
- 1939 Was the final year on the market as the motorcycles were not built after the end of the war.