Astira UltraGel 3000 Box Top. UltraGel has a clever comfort layer, offering supreme comfort, and unparalleled pressure relief; it comforts you as you lie down, but bounces back too, allowing you to toss and turn effortlessly without any partner disturbance. 2000 Mirapocket and 1000 mini springs for zoned support. Mattress is displayed in the illustration on a Silentnight Octavia Bedstead. The mattress is available in a Medium/Firm tension or a Medium/Soft tension. Also available as a 3', 4', 4'6" or 6' mattress.