KFS Stores is proud to carry a Serta mattress line that is specifically catered to work seemlessly with your Discovery World Furniture kids beds to provide your child the best possible sleep. While choosing a mattress for your bunk bed please remember that only mattresses 8″ thick or less can be utilized for the top bunk. This mattress thickness limit ensures that the guardrail height remains within safety compliance. All trundle mattresses should also be limited to an 8″ roles mattress to avoid rubbing while opening and closing the trundle. The Crayola Mattresses are a great option if you are shopping on a budget. These great tufted coil spring mattresses feature the fun and colorful Crayola design on the soft and durable polyester cover.