Using traditional Bonnel style coils, The Green Nest Quilted Organic Innerspring mattress is surrounded with quilted layers of organic cotton and wool with a little extra padding. The result is a medium-firm mattress in which the coils have not been treated with any oils or chemicals. The cover is 100% Organic Cotton fabric and its layers of pure wool act as a flame retardant. The electrically tempered steel coils have no plastic or chemical coatings. Features: Multilayered pad construction prevents padding migration and maximizes longevity. Carded Organic Cotton adds comfort. A layer of Pure Wool acts as a natural dust-mite repellent.