These replacement pads are for a great little trainer unit that gets a workout at my CPR/AED training classes. I use one trainer and the class takes turns using it so the pads have to last. These do a good job, holding up to repeated use. I estimate I have used the same pads at least 40 times before they begin to lose their effectiveness. I use Prestan manikins, and they adhere well to the material. Buy a few extra pairs and you'll never have a disappointing simulation, with an AED trainer you cannot use.