Astatic N50/51 originally used in a few later American Wurlitzers until the 1050
As the original cartridge may have been replaced over the years it is worth while comparing the picture with whatever you have fitted.
NOTE colour may vary
Replacement needle for Shure M75 c Cartridge. Often fitted in Ami and Rowe Ami, Wurlitzer including early OMT vinyl and some Rock Ola
A common error is to fit Type 75 needle when it should be a type 44 etc