The Air Jordan 21 (XX1 or XXI) PE - White / Metallic Silver - Varsity Red were released on November 4, 2006 and retailed for $150. They feature a white leather upper with black accents, as well as the adored taxi design on the outsole. They feature an interesting lace cover, which works as a flap. The extra high ankle cut is great for basketball, as they provide plenty of support around the ankle area. Other technical specifications include a double-overlasted phylon midsole supporting four I.P.S.(Independent Podular Suspension) pods on the outsole. There is a carbon fibre shank plate in the midsole, as well as an improved I.P.S. technology with interchangeable heel Zoom air pillars or encapsulated air pillars. It is not recommended that you play basketball in these, as they do not provide enough support around the ankle, and can cause severe ankle sprains.