Like a sentry's shield, the 12 in. Sentry Firm Hybrid Mattress is built for strength, endurance, and unwavering support. this mattress is engineered for exceptional durability, spinal alignment, and pressure relief, making it ideal for those who prefer a firmer sleep surface. This hybrid mattress combines individually pocketed coils with CertiPUR-US certified foam, delivering enhanced lumbar support, superior motion isolation, and long-lasting comfort. The reinforced firm structure ensures minimal sinkage while keeping your spine in proper alignment, reducing aches and pains. Each individually wrapped coil is designed to enhance durability and provide targeted support where you need it most. The premium quilted cover, made from densely woven, breathable fabric, offers a cool and comfortable sleep surface, ensuring you wake up refreshed and recharged. Unlike traditional mattresses, this hybrid model is fiberglass-free and crafted with CertiPUR-US certified foams, ensuring a safer, healthier sleep environment. It is roll-packed and shipped in a box, making setup effortless-just unbox, unroll, and let it expand. Compatible with all standard bed frames. Higher Coil Count for Superior Performance by Size: Twin: 480 coils (Extra support for a firm, stable feel); Full: 690 coils (Enhanced firmness and longevity); Queen: 800 coils (Superior spinal alignment and motion isolation); King: 1,024 coils (Reinforced structure for even weight distribution). Material: Polyester.