Used for a couple of weeks but we decided our mattress needed replaced which came with a topper.
The slight discolouration of the topper is how it comes, we've always used a protector on it.
Bought from Ghostbed, description below. Retails currently for $335.
7.62cm of contouring & cooling gel memory foam Designed to make your mattress softer CertiPUR-US® certified Made in the USA