On the end of the pen are two dials with a (+) and a (-) at either end. The outermost dial adjusts the extrusion speed. By rocking the rings in the direction of either the (+) or (-) you will increase or decrease the speed. The new speed will be displayed on the LCD screen. Adjustments towards the (+) will take the pen to a maximum speed of 8. Adjustments towards the (-) will take the pen to a minimum speed of 1. The slower the material extrudes, the faster it will harden. If you change the speed setting, the new speed will show on the LCD for a few seconds as the pen adjusts.
Each material for the 3Doodler PRO has an optimum extrusion speed and temperature, but you can adjust them to get the exact flow that you’re looking for.