Banjos without tone rings often have tone hoops. This tone hoop is a steel rod that sits between the wooden rim and the banjo head. This photo shows exactly what one would see upon removing the 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.