PF stands for Posture Foundation. Developed in 1933, this patented insole technology set a new standard in sneaker comfort. PF Flyers had the first collaboration between a sneaker company and pro athlete in the 1950s, when they teamed up with the famed Bob Cousy of the Boston Celtics. Today the PF Flyers line has "reclassified the sneaker" with modern materials. The men's large size line is available in sizes 14, 15, & 16, with some styles going to size 17.