I thoroughly tested this little device and man is it awesome, the heat is almost instant and gets nice and hot to the touch not simply "warm" on the highest setting. The controls are fairly simple to use (it's just 1 button). The flashlight is a nice convenience. I like that it can charge a phone as well. I'm sure my grandmother will love it. The vibration function was kind of weak but with all the other outstanding features I wasn't worried in the slightest.