1724134 Firmness: Super Firm A firm sleeping surface ensures restful sleep for your little bundle of joy. The Serta Tranquility crib mattress features firm, balanced support throughout with heavy gauge coils, corner supports and full perimeter border wire. It features an easy-to-clean, laminated cover. Cover is adorned with an adorable Serta sheep pattern. Features: -Mattress. -Tranquility collection. -Additional support provided by a polyester layer for a comfortable sleeping surface. -Exceeds federal and state flammability standards (16 CFR part 1633). -Security of edges assured by heavy duty cloth binding with lock stitching. -Stronger than vinyl. -Lock stitching prevents the entire binding from unraveling if any threads become loose. -Mattress also fits toddler bed frames. -Top inside layer is Serta Fireblocker, providing gentle sleeping and safety using exclusive material. -Cotton blend top layer ensures extra comfort. -Balanced support from full perimeter border wire as well as 4 corner supports for firm edges when baby is standing. -4 Mattress vents to keep sleeping environment fresh with natural air circulation. -Flex mesh support prevents the loss of cushioning. -4 Side flex clips and 4 corner supports for added firmness. -Dual Sided - Stage 1 for baby"s slumber and Stage 2 for an active toddler. -Stage 1 Infant Side provides a safe, eco-friendly sleeping environment through a layer of ortho-insulator and a layer of organic cotton. -Stage 2 Toddler Side provides a safe. -Eco-friendly sleeping environment through two layers of organic cotton. -10 Year warranty. -Made in the USA. -Dimensions: 52.5" H x 27.3" W x 5.8" D.