The Porter-Cable 7539 is a well-balanced 3-1/4-horsepower 5 speed plunge router, and is easily one of the most powerful, accurate and dependable routers around. With minimal vibration and the most precise cuts, the Porter-Cable 7539 plunge router is ideal for pattern and groove cutting, trimming and shaping, window cutting and chamfering. The 6-position depth rod with adjustable turret makes stepped or repeated plunge cuts easy. The 5-speed router runs off 110 V AC only and is rated at 15 amps. The Porter-Cable 7539 comes with an electronic, soft 5-speed start delivers 10000,13000,16000,19000 and 21000 rpm for different router bit cutting diameters and applications. The toggle switch feature allows the user to gradually increase the speed from 10000 rpm to 24000 rpm. The cable maintains a sustained speed even with a heavy load. The on/off switch also helps to restart the router in case of overheating. The slow start and gradual increase in speed decreases the initial torque and thus avoids the possibility of the Porter-Cable 7539 twisting out of hand. The problem of frozen bits and need for rapping of the collets is negated by the auto release collets system feature with ½" collet capacity. The Porter-Cable 7539 5-speed plunge router has a large bit capacity and it can work even with 4 inch bits. The 7539 router weighs 17lbs, has a base diameter of 7", and comes with 100% sealed ball bearings.