Duraspring Spring System. Soft Mattress Feel. Hand Tufted. Fibre Fillings. The Freestyle Soft mattress from Airsprung contains the Duraspring spring system which has a 13.5 gauge spring system made from high tensile wire giving an increased performance. The mattress has a soft feel & is hand tufted as well as this it is also filled with man made fibre fillings. The Freestyle Soft mattress from Airsprung is suitable for a wide range of our divan bases & bedsteads on our website. The Freestyle Soft Mattress is the ideal choice for those looking for a soft mattress.