Made with a 4.5″ natural latex core and covered in our untreated, natural wool moisture resistant fabric which is the same natural fabric we use for our moisture resistant pads. This natural wool outer will help to repel liquids, keeping the natural latex core in good shape. Because wool is a natural fire-retardant, we do not use any fire-retardant chemicals in or on this organic crib mattress. We also carry organic fitted sheets to complete the set. Size 28 x 52 x 4.5″.