The needles are 0.5 to three millimeters long. A dermaroller is an ordinary tool for microneedling. It’s a small wheel with rows of nice needles all around it. Rolling it along the skin could make up to 250 tiny holes per sq. centimeter. Your physician co... https://product01.netpro.co.kr:443/bbs/board.php?bo_table=free&wr_id=7