This is an antique carbide or acetylene bicycle headlamp manufactured by the 20th Century Manufacturing Co. in the United States. The unit is constructed of metal, likely brass, which has developed a dark, heavy patina and extensive surface oxidation. The lamp features a prominent convex glass magnifying lens at the front and a faceted red glass jewel lens on the side used for side visibility. The design includes a pierced ventilation chimney at the top and a cylindrical fuel reservoir at the base. The top cap is embossed with the words TWENTIETH CENTURY separated by stars. The rear of the housing features embossed text reading 20TH CENTURY MFG CO., MADE IN U. S. OF AMERICA, and PATENTS AND DESIGN APPLIED FOR.