Subrtex High Density Cooling 4" Gel Memory Foam Mattress Topper (Twin) in the Mattress Covers & Toppers department at Lowes.com
Amazon.com: IULULU Mattress Topper, Made in USA, Full Size Gel Memory Foam Bed Topper, Soft Foam, Pressure Relief for Back Pain, 2 Inch, Light Blue (JA-US-2F) : Home & Kitchen
Sealy Essentials 2 Inch Mattress Topper, King Blue F02-00222-KG0 - Best Buy