0.25m for use with one of the Genosys serums. 
CE and ISO certificated, Medical Grade Stainless Steel needles. 
This prestige device is a durable, high quality, precision tool. It uses multiple very fine surgical stainless steel needles aim to injure the skin sufficiently enough to stimulate collagen and elastin. The resulting micro-channels also aid in infusing therapeutic serums for greater penetration and overall efficacy.