We traveled around the world to make sure we got the best possible roller available. We went to several different manufacturers, testing the products and giving all the products tests to make sure they would match up. Additionally, we made sure the factory was clean and well-maintained, there weren't any toxic ingredients in the plant and the needles were sharp and unbent.
Be careful of needles that have a 'bent or hook' in them. These can tug at the skin and incur scarring (instead of curing it)