If you deal with painful cramps or back pain, you should check with your doctor before using this.
Promising review: “So far, this product has worked wonders for my cramps! I ordered and received this product yesterday, and I am super happy with the outcome. I like the vibration options, but I’m perfectly fine with just the heat. The temperature can get pretty high, so I would suggest not to apply it directly to the skin. Overall, I am satisfied with my purchase and will certainly recommend to friends and family!” —Jasmine
Get it from Amazon for $29.99+ (available in 11 colors).