Sleep Master’s 6 inch Bonnell spring twin mattress is just the right mattress for growing children or young adults. This quilted tight top mattress is great for bunk beds, day beds and trundle beds. The Bonnell spring system is made from heavy gauge steel coils to provide firm support. The top is quilted with layers of fiber padding and foam for comfort. 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.