MRC:
The specification,standard,or manufacturers reference,and the classification designation,such as class,condition,temper,and the like,that identifies the material.MDCL
Material Specification:
Mil-s-5059, comp 302 military specification single material response or mil-s-5059 military specification single material response or mil-s-7720, comp 303 military specification single material response or mil-s-6721 military specification single material response or qq-s-763, class 303 federal specification single material response