Bundle of Dreams 3-Inch Extra Firm Mini Crib Mattress is made with an Organic Cotton, removable and machine washable cover that's also water repellent. The 100% Breathable mattress not only helps regulate temperature by allowing air to pass through the entire mattress, but there is no off-gassing (that chemical smell when you open a mattress with foam), harmful VOC's and no toxic emissions. All materials used are eco-friendly, hypoallergenic with a bundle fiber core for optimal breathability. This mattress offers two different firmness levels on either side of the mattress. Lightweight and portable, make it a great option for traveling. This mattress is GreenGuard Gold Certified.