Penis traction devices are medically proven to increase penis size. They are a great tool as a stand alone, or in combination with other enlargement techniques such as hanging/stretching. Although, I'm not too impressed with noose/loop designs because they cut off blood supply somewhat making long sessions troublesome. I use a vac extender that creates expansion to secure the glans and does not limit blood flow. I'm not even sure if my my extender model is still being manufactured currently, but if I we're to compare the vac to the noose the vac wins in every category.
Check out this study in The Journal of Sexual Medicine
Penile-Extender Device in Increasing Penile Size in Men with Shortened Penis