How many times have you come across an ad on the Internet that shows an illustration of a penis being extended with a device to 3 or even 4 inches your normal size?  Well that's simply not possible, and the reason why is because these devices do not offer that much support, they are not strong enough and custom built to your specifications.
  They are all built in the same way and meant to work on everyone, but that's just not going to do the trick I'm afraid.
  At least with exercises or other natural methods you can choose the strength at which you pull or milk your penis, so it will show gains that contraptions simply cannot show, no matter how much you use them.
Why are they made the same way? They are all made the same way, because the manufacturers know that people will buy them, did you know that they are made for a tidy $50 per device but you can expect to pay well of $250?  Now that's what I call cheeky!  Each contraption works the same and offers the same resistance no matter who is using it, so this is a major floor already, if you have a problem that is unique and will affect your overall growth, then how do you suppose a one size fits all product will make your manhood any longer or wider? Can I make my own? Yes you can in fact make your own and there are plenty of instructional courses on how to do so, but it's strongly advised that you don't, the reason being is because you are not a professional so it's much more likely you will create something that will not work and could possibly cause long term damage.
  The best option for you is to stick with the all natural route.