Get a start on better sleep with the Kelburn II twin extra-large mattress from the Sealy Hybrid Performance™ collection. With exclusive Posturepedic Technology™ like the Response Pro ZONED HD encased coil system, you'll enjoy durable all-over support with 20% more coils in the middle of the mattress—a spot where you need it most, especially for your back. This densely packed system of hourglass-shaped coils with a dual-stage design ensures more personalized support. Each coil moves independently for more targeted support. Plus, extra support is found around the mattress's edges with the DuraFlex™ coil edge system. Its high-density, flexible coil border surrounds the mattress for better edge support, more usable sleeping surface and improved durability. When it comes to comfort, Sealy's UltraStretch ComfortLoft™ cover with MoistureProtect™ works with Immersion™ advanced memory foam with Chill Technology™ to deliver a cool feel. The cover is designed to draw moisture away from your body, while the advanced memory foam with a slower response allows for a more breathable, cool-to-the-touch sleep surface. Below the surface, SealyCushion™ extra soft foam offers ultimate comfort with a high quality cushioning foam used in the quilt and comfort layers. Foundation/box spring available, sold separately.