• 23cm +/- 1cm• Hard/Hard• Foam Plus• Felt• Steel Bonnel Springs (384 Springs)• Felt• Foam Plus Sleeping mattress from Bonnel springs, Felt and Foam Plus. Bonnel springs give an absolute sense of support and stability. Foam Plus is a high density and strength foam material for great elasticity, flexibility and uniformity that ensures the maximum performance of the mattress behavior. The mattress is surrounded by ecological fabric with antibacterial certification.