Feature: Made of ABS plastic case non-toxic safe and durable. The advanced air compressing system shock mitigation system and multilevel muffler helps to make noise low. 4 rubber feet design also helps reduce vibration noise produced by the machine while working. The air output can be adjustable so as to satisfy your various demand best for small and medium-sized fish tank plus oxygen. Double and four holes large gas output. Environmental product energy saving and long life. By using it the environment of fish can be greatly improved so that fishes or turtles can play freely and live a healthy life. Specifications: SB-748 (Double Holes) Rated Power: AC 220V-240V Power: 8W Air Output: 2 x 3.5L/min Cable Length: Approx. 1m Size: 150 x 70 x 70mm SB-848 (Double Holes) Rated Power: AC 220V-240V Power: 12W Air Output: 2 x 4.5L/min Cable Length: Approx. 1m Size: 160 x 80 x 80mm SB-948 (Four Holes) Rated Power: AC 220V-240V Power: 8W Air Output: 4 x 3L/min Cable Length: Approx. 1m Size: 180 x 140 x 90mm SB-988 (Four Holes) Rated Power: AC 220V-240V Power: 12W Air Output: 4 x 4L/min Cable Length: Approx. 1m Size: 180 x 140 x 90mm includes: 1Aquarium Air Pump 1Instruction Manual