The Hardin 9664 3-1/4 HP Router Motor with External Speed Control is designed for high-power routing performance in router table and router lift applications. The 15 amp motor delivers variable speed performance from 10,000 to 21,000 RPM so users can match cutting speed to the router bit and material. Soft start and electronic constant speed control help the motor start smoothly and maintain steady performance under load. The ER20 collet system includes 1/4" and 1/2" self-releasing collets for secure bit holding and improved cutting precision. The motor is built with a rugged aluminum housing and sealed bearings for high-speed routing environments. Its 4.2" motor diameter fits most router lift systems designed around the Compatible with Porter-Cable 7518 motor standard. The large and heavy-duty external speed control switch provides easy-to-reach speed adjustments from above or outside the router table and includes a precision-dampened dial with an LED tachometer for quick RPM reference.