 British licensee Sheffield-Simplex began production of Ner-A-Cars in 1921 with the original American design with the 221 cc two-stroke engine and the friction drive transmission In 1923 the engine was enlarged to 285 cc, with a 70 mm bore and a 74 mm stroke.Sheffield-Simplex developed a new version with a Blackburne four-stroke side-valve engine, displacing 348 cc with a 71 mm bore and an 88 mm stroke, driving through a three-speed Sturmey-Archer manual transmission.This version was introduced in 1925 as the Model C, with the earlier two-stroke friction-drive model continuing as the Model B.