The Air Jordan 21 (XX1 or XXI) Low – Black / Metallic Silver – Varsity Red were released on November 2, 2006, and retailed for $135. They feature a black suede upper with red accents,but are a low top version of the Air Jordan 21 (XXI). They still feature technical specifications such as breathable textile uppers, 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.