Under Armour Women's UA Speedform(tm) Fortis 100% Mesh Imported Synthetic sole Shaft measures approximately 2" from arch ArmourVent Mesh Technology - Delivers true breathability in a light, stretchy, durable, fast-drying jacquard knit fabric. Smooth, Ultrasonic Welded Seaming - With Bemis tape for next-to-skin support and comfort. Seamless Heel Cup - With silicone grip for a locked-in, anatomical fit. Adjustable Lock Down Heel Strap - Improves fit. 6mm Moulded 4D Foam Embedded Within The Sockliner - For added cushioning and moisture wicking capabilities paired with seamless comfort.