The Serfas Dual Density line of saddles is constructed using their patented I.C.S. (Infinite Comfort System) technology. Made up of a soft flexible rubber base followed by two layers of soft and firm closed cell foam, and a final top layer of friction reducing Reactive Gel covered in moisture-wicking four-way stretch Silk-Tech Lycra. Features Serfas Silk-Tech four-way stretch moisture-wicking Lycra cover, Dual Density Progressive Foam Technology, steel rails.