THE MOST DURABLE VAPOR TO DATE. The NikeCourt Air Zoom Vapor Cage 4 is innovated to withstand your toughest matches-thanks to an updated design that puts flexible, durable materials exactly where they're needed the most. A unique lacing system keeps your laces hidden for extra durability while sliding. Exceptionally Durable - The data-informed design places flexible, durable materials exactly where they're needed the most. The outsole material wraps over the midsole on the medial side for durability. Responsive Cushioning - A Zoom Air unit beneath your forefoot creates a springy sensation with every step. Supportive Feel - Unique lacing wraps your foot for support while you move. The medial eyestays are covered for added durability while sliding. More Benefits - Stiff frame on the lateral side creates a stable feel during side-to-side movements. 1-/2-length sleeve gives you a sock-like fit. Designed for use on hard court surfaces. Product Details - Removable insole.