Product Description: The 25cm TightTop Spring Mattress by Zinus features hundreds of independent iCoils providing customized support while minimizing motion transfer for uninterrupted sleep. It is topped with four layers of comfort and high density foam for customized rest. The stable support layer is the 19cms iCoil Pocketed Springs. The 19cms ;iCoil Pocketed Springs provide stable support, keeping you aligned and pressure free for a great night's sleep. Please open your mattress package within 72 hours of receipt and allow 48 hours for your new mattress to return to its original, plush shape.