This is the second version, MC-X lens line. Production years 1973 – 1977
Built-in Filters: 1A, Y48, 80B, O56. Lenses for the north american market got the appendix ‘-X’ right after the ROKKOR name on the front marking, colored in bright orange.
THANX TO: Andrea Aprà and eazypix.de for all the information.
please visit http://minolta.eazypix.de/lenses/ to gather all the information about versions and variants and on Minolta lens families.