Supercoil Spring System. Fibre Fillings. Medium – Firm Tension.The Ortho Comfort by Airsprung is from the comfortably firm range, it offers medium to firm support. The mattress contains a supercoil spring system which is an extra heavy 12.5 gauge bonnell spring system which is made from a high tensile wire built for an increased performance. The Comfort Ortho by Airsprung is filled with man made fibre fillings and has a platform top base which comes with a variety of draw options.