Vintage 90's Red Wing ANSI Z41 PT91 MI/75 C/75 Cognac Leather Steel Toe BOOTS Mens Size 12 Line #1: ANSI Z41 PT83: This line identifies the ANSI standard. The letters PT indicate the Protective Toe section of the standard. This is followed by the last two digits of the year of the standard with which the footwear meets compliance (1983). Line #2: M I/75 C/75: This line identifies the applicable gender [M (Male) or F (Female)] for which the footwear is intended. It also identifies the existence of impact resistance (I), the impact resistance rating (75, 50 or 30 foot-pounds), compression resistance (C) and the compression resistance rating (75, 50 or 30 which correlates to 2500 pounds, 1750 pounds, and 1000 pounds of compression, respectively). PT83: Made from 1983 through 1991. The vertical tag and toe tracks are usually indicative of early 1980's models. This model is more desireable in the Japanese market and the vertical tag can bring in at least an extra $50 to $100 over the PT91's and 99's.