I have found it to be so in my case. I still do a little manual, but I've had far more gains with the [words=https://shop.mattersofsize.com/products/sizegenetics-penis-extender]extender[/words] and hanger. I can get more tension for longer periods with devices. Others have had great gains with manual exercise. The thing is you have to stretch your dick in some way to make it longer and expand it to make it thicker. Experiment and find what works best for you.