Spa Sensations 6 Bunk Bed Spring Mattress, available in Twin and Full Size by Zinus. The Spa Sensations 6" Bunk Bed Spring 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. If even and perfectly cushioned support strikes your fancy, then the Foam and Spring Mattress is your ticket to many well-rested mornings to come. The heavy duty coil system is made from heavy gauge steel coils to provide firm support. This mattress is especially ideal for stomach sleepers and those who enjoy a reactive feel. Rolled and shipped in a box that arrives at your doorstep with a 10-year worry-free warranty in tow, it’s equipped with just about everything you need to enjoy smooth snoozing. So all that’s left for you to do is tuck in and close your eyes, no sheep-counting required.