Bicycle from 20s with rare German auxiliary engine, Phantom.
Phantom-Werken, Engen&Auders (later Phantom-Motoren-Fabrik, Gebr. Henke&Bittner) was a company based in Berlln, established in 1921, closed in 1928. They were sellling 148cc auxiliary engines for bicycles and their own motorbikes, powered with 148cc - 246 cc proprietary engines. In mid-20s they were using British JAP engines (173cc - 490cc) as well.