This Cal King Firm-Top Mattress boasts of High Density Micro Coils, made up of over 2,000 individually encased springs, hand-crafted with ultra flexible wire coils. In the upper comfort layers, High Density Micro Coils bring support points closer to the body’s contours. Pocket Springs Units and Premium InnerSpring units provide additional coil-on-coil support. This flexible wire enables circular coil movement, enabling the mattress to swiftly respond to your body shape for exceptional comfort. Handcrafted in the USA.