The 6-element 4-group Omicron EL was made by Sankyo Kokhi for the Omega enlarger company (Berkey Marketing Companies, at that time). The same lenses were also marketed as Beseler Color Pro for the Charles Beseler Company and as Komura—one of Sankyo Kokhi’s brands (Komura and Chibanon).
The fit, finish, coatings, and optical performance of my 90 mm f/5.6 Omicron EL is identical to that of the EL Nikkors from the same period (excellent).
http://www.khbphotografix.com/Used/Omicron.htm