The Air Jordan XXII (referred to in advertisements as XX2) was released on February 17, 2007 on Michael Jordan's 44th birthday. It retails for $175, although Niketown.com had a special discount ($125) the day it was released and offered free shipping with it as well. The aggressive and sharp design is said to be inspired by the F-22 Raptor fighter jet. Some technical features of the shoe include the return of the Independent Podular Suspension (IPS), as featured in the XX and XXI, and a titanium shank plate to provide midsole support. It also includes two pairs of interchangeable heel pillars similiar to the ones found in the Air Jordan XXI, although this time the Zoom Air pillars contain double-stacked Zoom Air units.