Alien High Efficiency Air Stone 

• Quality black corundum higher density stone
  
  
• Creates finer bubbles for increased aeration efficiency with no increase in pressure 
  
  
• Sucker clips for airline available separately 

The ALIEN®️ black series air stone is made of quality Black Corundum Stone which is  sintered at 1500 Degrees Celsius and is of a higher density and quality than green, blue or even white corundum. It is a relatively small stone at 50mm but punches above its weight by using the air more efficiently creating finer bubbles for increased aeration with no increase in pressure.