The unit consists of a metal base and an electric motor which runs a metal wheel with a leather strap. This unit is stored in a metal cylindrical container.Handwritten label on object reads: "This machine is for direct current only. All plugs in this [.] are AC
AUTOMATIC / COMPRESSOR UNIT / PAT'D NOV. 30-09.. DEC. 6-10. / SERIAL NO 5194 CYCLES / STYLE 37 / ELECTRO DENTAL MFG. CO. / PHILADELPHIA, PA., U.S.A. Maker's Plate
ELECTRO PNEUMATIC CONTROLLER / NUMBER C4867 / ELECTRO DENTAL MFG. CO. / PHILADELPHIA, PA. / PAT'D. MAY-4-09. MAR-11-13 Maker's Plate
Electro Dental Manufacturing Company. Compressor - Dental, F1646.2004. The Museum of Transport and Technology (MOTAT).