Convenient to operate without oil. Cylinders and pistons are made of premium materials, making the pump strong and durable. This unit features dual (2) 1/4 inch variable output outlets and uses 6.0 watts of electricity per hour. 4.5 liter per minute total output at 1.75 PSI per outlet. Measures 6.5 inches long by 3.75 inches wide by 3.4 inches tall, weighs 1.3 pounds. Uses standard airline tubing.