Miracoil Sleep. Miracoil springs and EcoComfort Fibre. The Miracoil system has three zones with varied levels of tension for great support in key areas and is designed to minimise roll-together and roll-off. EcoComfort Fibre is a Silentnight exclusive material with great natural heat relieving properties for a cool night's sleep. A hard wearing damask cover microquilted in place. 5 year warranty. And buy this Miracoil Sleep Was £179.00 Now £169.00.