Miracoil Sleep Silentnight. 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. So buy this Miracoil Sleep Silentnight Now £179.00.