Koi Beauty Titanium DermaStamp Vertical Micro Skin Needling Tool Length of needle 0.25mm The Koi Beauty DermaStamp is a convenient, safe to use skin needling system. The precision engineered medical stainless steel needles penetrate the epidermis of the skin and provide penetration pathways to enhance the absorption of topically applied skincare. SanDine Derma Roller 540 needles Length of needle 0.25mm Efficient system for skin exfoliation. Titanium needles for longer and safer use. Both tools are brand new. Never been used and still in sealed protective covering.