Dermarolling is also known as micro-needling, skin rolling or collagen induction therapy (CIT). Derma Rollers are made of many high grade micro needles which roll over and penetrate the skins upper surface painlessly. These revolutionary devices provide two major benefits.
Firstly, they stimulate collagen growth which significantly improves the appearance of scars, fine lines, wrinkles, stretch mark, and acne scars.
Secondly, they allow the transdermal application of creams, gels and oils, to be absorbed far more effectively - boosting their effectiveness massively. This is relevant to hair loss treatments as well as cellulite reduction. 
1, Derma roller is used for one of the following skin problems:
1) Scar Removal – including acne scar removal / treatment 
2) Stretch Mark Removal / Treatment 
3) Anti Ageing,Anti Wrinkle 
4) Cellulite Treatment / Cellulite Reduction or Removal 
5) Hair Loss Treatment / Hair Restoration
6) Hyper Pigmentation Treatment 
2, When using different kinds of needle?
You should choose the roller which will be suitable according to its purpose of treatment before operation.
Different use examples:
1) For the improvement of the skin color:0.2,0.5
(used for improvement of the whole skin color,for the solution of partial pigmentation problem,etc)
2) For the skin regeneration:1.0 1.5
(used for solutions of thin epidermis,thin wrinkle,decline of elasticity,etc)
3) For the antii-ageing&rejuvenation of ruined skin:1.5 2.0
(used for solutions of thick wrinkle,large pore,injury scar,pimple scar,severe decline of elasticity,etc) 
3,How to use:
Follow 3 steps of needling to enhance forming channels
Horizontally-vertically-diagonal
Each step has to be repeated 3 times at once.

4,Clean the Derma roller
Soak about 5-8 minutes with 75% alcohol,Or use ultraviolet to disinfect for about 45 minutes.Do not use autoclaves,steam and high temperature sterilization methods
5,Caution
1)Don't re-use head
2)Do not share with other person
3)Do not roll too much more than indicated time.If treated skin shows hypersensitive response, consult with your doctor.
4)Keep the micro needle part always clean
5)Store in a safe place out of the reach of children
Specifications:
Needle material: Stainless steel
Needle length:0.2/0.25/0.3/0.5/1.0/1.5/2.0mm
0.2mm for home use
0.5mmfor clinical use
1.0mm for medical use
1.5.2.0mm for physician use
Needle number:540pcs needles
The size of drum:1.8cm(width)*2cm(diameter)
Packing size: 35*35*33cm/50pcs weight:8kg