Mattresses Mattresses Rhine 4 INCH FOAM Solstice Sleep A new 4 inch foam mattress. Perfect for bunk beds campers and kids rooms. Firmness Medium Soft Best For Kids Support Core Foam Base Mattress Twin 21737-1010 TWIN $79.99 Mattress Full 21737-1030 FULL $99.99 Mattress Queen 21737-1050 QUEEN $139.99 Mattress King 21737-1060 KING $169.99