Instruct: Classify a given review into positive or negative sentiment.
Query: very helpful for bad backs

I've had back surgery and am in a low level of constant pain. Now with this mattress topper I don't get up in more pain than I went to bed with. Really helped some hip pain too. Glad I purchased this topper rather than buying a new mattress. Helpful that it comes w/a mattress cover that fits the extra height and haven't had trouble w/my regular sheets going on the bed. My dog loves it!