I purchased this mattress cover because I knew it was an approved mattress protector by Simmons for warranty purposes. I have no idea why it was so expensive. It looks to me to be a rather simple product of simple design. I haven't spilled anything on the bed to test the product out, nor do I have intentions to do so. I suppose if after a few months there aren't yellow stains resulting from night sweats on the new mattress I purchased, then I can say it does what the manufacturer claims it does.