Special Sleep. An entry level Miracoil mattress. Miracoil is a no roll together open coil spring system exclusive to Silentnight. The cover is high density stretch fabric which is micro quilted in place. EcoComfort Fibre fillings are scientifically proven to dramatically reduce heat build up, allergens and dust mites. 5 year guarantee. So buy this Special Sleep Was £159.00 Now £155.00.