A half-zipper closure gives the HOLLY knee boot a calf-defining fit while an angled block heel and a square-toe giving this style a sharp finish. Square-toe block heel knee boot Side half zipper closure Angled block heel 2.75 inch heel height Size 6 measurements: 12.40 inch shaft circumference, 14.25 inch shaft height Size 8 measurements: 13.19 inch shaft circumference, 15.5 inch shaft height Size 10 measurements: 13.98 inch shaft circumference, 16 inch shaft height For correct calf measurements, measure your bare calf at its widest circumference with your foot flat on the ground Features stretch material for a flexible fit - may allow for additional calf circumference beyond listed measurements Vegan leather upper material Textile lining Vegan leather sock Synthetic sole Fit tip: If you are in between sizes, size down a half-size Imported Steve Madden HOLLY BLACK 5.5 Steve Madden Women's Holly Block Heel Boots - Black - Size 5.5 - Leather