UOC code tells you what model the NSN can be used on. For instance, on the 60 KW. There is a MEP-115A, (400 hertz). There is a MEP-105A, ( 50\60 hertz precise power, read that as electric governor). And last but not least, the MEP-006A, (50/60 hertz utility, read that as non electric govenor)...