Convenient to operate without oil. Cylinders and pistons are made of premium materials, making the pump strong and durable. Large unit that features four (4) 1/4 inch variable output outlets and uses 12.0 watts of electricity per hour. 9 liter per minute total output at 1.75 PSI per outlet. Measures 7.75 inches long by 5.7 inches wide by 4.2 inches tall, weighs 2.6 pounds. Uses standard airline tubing.