Estrella Visco-Gel Quality Mattress. Conventionally sprung (Bonell Type). 26cm deep +/- 1cm. Inner core of Bonell spring. You choose which side of mattress to use VISCOELASTIC or VISCOGEL with carbon particles. Both sides have a natural fibre layer to increase freshness. Price is for standard 135x190cm size. All sizes upto 180x200cm. Made in Murcia.