Mares Avanti Quattro Open Heel Fins Size Chart
  SM REG XL
US Men's shoe size 6-9 9-11 11-13
US Women's shoe size 7-10 10-12 12-14
European Men's shoe size 38-43 43-45 45-48
Length (inches) 24 24.5 25.5
Width (inches) 7.7 8 8.3
Weight (pounds per pair) 3.3 3.75 4.4

These are general guidelines only, sizes are not guaranteed. But no worries, since at LeisurePro we offer our exclusive PFF Guaranty