A thick double-wall outer casing, integrated pump well and noise-suppressing baffle chamber make the Q2 one of the quietest air pumps to date. Q2 is quality constructed to provide lasting and reliable performance for aquariums up to 600l. 

• Ultra Quiet
• Powerful
• Reliable
  
• 216lph
• 2.41 psi
• single outlet
• 4.5 watts
• 45 dB
• 2 year warranty

We have used this unit and it can easily run 1/2 dozen air stones at a 1m depth. Great little air pump for the money.