Detail showing the relationship between the flange and the hooks/nuts system of applying and adjusting tension to the banjo head. This banjo is thought to be a 1930s era Slingerland. The Slingerland Musical Instrument Mfg. Co. was based in Chicago, Illinois and was owned and operated by H.H. Slingerland. The company changed names several times, including The Slingerland Banjo Company, Slingerland Banjo and Drum Company and others.