Dual-layered Vanadium Wire Springs: Wire springs are 62 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 Classic Superb features two layers of vanadium wire springs. British Fleece Upholster: The Classic Superb bed is upholstered in British fleece wool for a soft, natural feel. Mattress Border: Each Classic Superb features a border that is 9.1 inches (23 cm) deep and reinforced with 3 rows of hand stitching on all sides. Each side of the Classic Superb has air vents to promote air circulation and ideal temperature regulation. Borders are upholstered in protective wool as a finishing touch, featuring piped ticking for added softness. Exclusive Horsehair Fill: The Classic Superb bed is the first in the Vi-Spring line to make use of an exclusively all-horsehair mattress fill. Horsehair is an all-natural temperature regulating fiber that enhances airflow while wicking away moisture. The result: An incredibly breathable mattress core that keeps you cool, dry, and comfortable throughout the night.