9" Standard Premium Foundation NBMCo. Direct $159.00 Twin - $159.00 Full - $179.00 Queen - $199.00 King - $358.00 Cal King - $358.00 Twin XL - $179.00 Size Twin Full Queen King Cal King Twin XL Quantity This option is currently sold out This is a 9" regular height heavy duty foundation. Foundations are also available in low-profile height of 5" and bunkie boards with a height of 1.5". Please note that king size is comprised of 2 txl boxes (already included in price).