Skin-needling is the penetration of the skin by very small needles. This can be in the form of a stamp type tool with a long handle or a roller. 
About Rollers:
	
Can contain 50-500 needles.
	
Quick and easy to do a treatment. 
	
Needles come in various lengths & gauges (width).
	
Downsides are they can cause more trauma due to the way the needle enters and leaves the skin.
About Stamps:
	
Contain up 50 needles. Smaller head means more control, and therefore you can work on smaller areas such as small scars.
	
Great for working on more delicate areas of skin especially around the eyes.
	
Great for scalp treatments.
	
They are time consuming to use and manual tools cannot puncture the skin as much as needed to cause sufficient trauma.
Skin-needling is called by many different names. It can be more commonly known as Derma Roller but this is trademarked in Australia and the USA by one company. Other names used to describe this treatment are Skin Needling, Percutaneous Collagen Induction (PCI), Collagen Induction Therapy (CIT) or Derma Rollering or Derma Needling.