each product contains derma roller 1 nos. Number of needles - 540, handle material - medical grade plastic. Needle material - titanium. What are dermarollers- dermarolling is also known as micro-needling, skin rolling or collagen induction therapy (Cit). Derma rollers are made of many 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. Stimulates skin regeneration reduces stretch marks & cellulite improves skin color and texture of aged skin reduces hyper-pigmentation removes very deep wrinkles and reduces acne scars.