Circuit Scribe Pen Lite Kit: Draw Circuits Instantly, Silver Non-toxic, silver conductive ink pen - Write on any surface your regular rollerball pen will! Kit includes 1x silver conductive ink pen, 1x Bi-LED (red & blue), and two coin cell batteries Resistance is 0.05-0.2ohms/sq/mil (2-10ohms per cm of writing) 60-100m (65-110yards) of writing per pen The most successful conductive ink pen - funded on Kickstarter by over 12,000 backers