This adapter cable allows you to power up to three (3) standard 3-pin or 4-pin computer fans from a DC power supply. The DC input measures 5.5mm x 2.1mm which is the most common barrel plug size, ensuring compatibility with a wide range of power supplies. Most computer fans require 12V for full speed operation but lower voltages like 5V and 9V can be used to achieve quieter operation. The cable is designed to a high standard with 22 AWG wiring and injection molded components for durability. Total cable length (including connectors) is 12 inches (30cm)