This aluminum Jacobs tone arm is missing the base, but it has been buffed and polished as seen - it looks like it has been nickel plated but it is buffed aluminum.

The Jacobs after market tone arm was widely used on Wurlitzer models 1015, 1080 and all other 24 play models except the 1100 and 1080A when a light weight crystal cartridge was desired. 

A pre-amp was also part of the kit but I only have the tone arm assembly.