The N20 12V 140RPM Micro Metal Gear Motor with Encoder is designed to operate at 12V but can run efficiently within a 3-12V range, with rotation starting from as low as 0.5V. While lower voltages may be inefficient, higher voltages could reduce motor lifespan. These motors come in various gear ratios from 5:1 to 1000:1. Except for the 1000:1 ratio version, all motors have identical physical dimensions, allowing for easy swapping to accommodate changing design needs.