We purchased 2" memory foam to go on our king-sized bed. We already bought new pillow-top mattresses but they were still lacking. We were tossing and turning all night. Purchased the memory foam and WOW does it make a difference. It shipped lightening fast. The smell dissipated quickly and it took it's correct form within 2 hours. We slept on it the day it came. Would highly recommend especially if your back hurts! Great price and great quality.