Airsprung Duraspring™ core mattresses are ideal for those who prefer their mattress to be a little more medium than firm in feel. The gauge (or thickness) of the high tensile wire used in the spring is known in the industry as 13.5 gauge. A helical wire (a wire that looks a little like a curly pig tail), runs across the bed and joins the individual springs together in rows. The 13.5 gauge unit is usually framed with a steel rod adding extra support and stability to the whole unit. The standard height of the Duraspring™ is 5½ inches (14cm approx).