It was invented to help diminish trauma and discomfort with oral piercings such as lip and tongue.

From this video review, we can see that it is also capable of having a tremendously positive impact on scar tissue!

For use on nipple or triangle piercings and certain other areas, you can cut off part of the disc so that it rests more comfortably against the body. 

You can purchase them here. The 5 mm mini discs fit 18 and 16 gauge jewelry and are suited to smaller bumps. They also stock 7 mm discs, which fit 18-14 gauge. The hole on these can probably be stretched to fit on 12 gauge as well. Custom and large-size discs are also available--up to 00 gauge! You can order them here.

As it says in The Piercing Bible section on scar reduction products:

"...ReJuveness, Epi-Derm, and other silicone strips and sheets; and Aroamas, Xeragel, and other silicone gel systems. It is believed that silicone helps scars heal by trapping moisture to increase hydration, and by suppressing over- activity of scar-related cells and normalizing their activity."

I personally used the disc on some excess scar tissue on the back of my own ear cartilage piercing and now it is perfect! The results are great and I think the NoPull Piercing Disc, is definitely worth a try!

I've also used them as little gaskets or washers on the top of VCH piercings for those with builds lacking much room for jewelry due to a pubic mound that presses against the top gem or ball. This prevents discomfort, excess scarring, and even embedding!

The images below depict before, (some during), and very impressive after results with diminished scar tissue from using the NoPull Piercing Disc!