The Cra-Z-Art Cra-Z Doodle 3D Pen is an amazing and fun all in one 3D creation system. Slide in your color 3D gel tube and adjust the tip. Squeeze your design onto molds or other surfaces. With the Cra-Z Doodle 3D Pen, you can build sections using molds and "weld" the parts together with the colored gel, then simply switch magic light on to harden. Create 3D Ultimate Vehicles - it's awesome! Takes 1 AAA battery, not included. Refill packs available.