Triple-layered Vanadium Wire Springs: Wire springs are 1.93 inches (49 mm) in diameter and come sewn in to individual calico pockets. Innerspring support system is hand formed into a honeycomb-nested unit. For added support and comfort, the Vi Spring Masterpiece Superb features three layers of vanadium wire springs. Mattress Border: Each Vi Spring Masterpiece Superb features a border that is 9.8 inches (25 cm) deep and reinforced with 5 rows of hand stitching on all sides. Each side of the Signatory features air vents to promote air circulation and ideal temperature regulation. Borders are upholstered with all-natural coir and wool, featuring piped ticking for added softness. Shetland Isle Wool Upholstery: The Vi Spring Masterpiece Superb features upholstery of authentic Shetland Isle Wool that creates a sleeping surface free of humidity and naturally regulates temperature. Fully Blended Layer of Exotics: The Vi Spring Masterpiece Superb also features a fully blended layer of exotic materials including cashmere, bamboo, and alpaca. No other luxury bedding company in the world boasts a greater collection of fine-quality filling materials, which is why no other mattress compares to the exquisite comfort of the Masterpiece. 100% Silk Cover: The Vi Spring Masterpiece Superb is the only bed in the world to come delicately enveloped in 100% silk.