I've had severe knee pain for five years, and it's been tough. I saw an ad for this device on Facebook and decided to give it a go due to their guarantee and the reviews. The shipping was slightly delayed, but once the massagers arrived, I immediately tried them out and to my surprise felt relief from the very first use. I've been using them for the last month now and my pain has reduced significantly to the point where I actually don't notice it anymore and can do my daily activities without any problems. Worth every single penny!