Product Review: Custom 3 LB Memory Foam Mattress Topper for RVs, Boats, Trucks, Sofa Beds (66x80 Olympic Queen) The Custom 3 LB Memory Foam Mattress Topper is a great option for those who want to add some comfort and support to their RV, boat, truck or sofa bed. The topper is made of high-quality memory foam that conforms to your body's shape for maximum comfort and support. It also features a 66x80 Olympic Queen size, making it perfect for larger beds. One thing I appreciate about this topper is its durability. It's designed to withstand the wear and tear of daily use, so you can be sure it will last for many years to come. Additionally, the topper is waterproof and dust mite proof, which is especially important when using it on a boat or RV where moisture and dirt are common. Overall, I would highly recommend this Custom 3 LB Memory Foam Mattress Topper to anyone looking for a comfortable and supportive addition to their bed.