PureLoft is filled with dermatologist-tested synthetic microfiber that mimics goose down in loft (full and fluffy), slow compression and bounce-back. Chamber construction gives you the benefits of two pillows in one: a denser inner pillow with greater support is cushioned with an outer layer of fill for comfort. All with a sateen weave that gives it a silky-soft feel. Choose firm density if you like to sleep on your side — medium if you're a back sleeper.Medium: Standard 24 oz; King 34 oz. Firm: Standard 28 oz; King 38 oz.Let's talk timelines. Synthetic stuffings have an average lifespan of four years. If you have allergies, your pillow should be replaced every two years. And high-quality down can last ten to fifteen years with regular washing and fluffing. No matter what the fill in your pillow, if the form is lumpy and uneven or you're experiencing back and neck pain, it's time for a replacement.