This sturdy 7″ Air Diffuser has a heavy base with a CNC bottom plate. The high quality epoxy of this air diffuser will not blow off giving you years of service. Normal flow for this air stone is 1.5 cfm. Less is better as the bubbles from this air stone are smaller and you get better oxygen and gas transfer. This 7″ air diffuser has a 3/8″ brass barb fitting to fit most 3/8″ ID hoses. Its made from compressed silica sand and made for many years of service. It will handle up to about 3.5 cfm. but best around 1.5 cfm. Used in most fish farming operations the air stone comes in many different sizes and shapes. The aerating stones can be 7′ round or 1.5″ x 1.5″ rectangular shape. When use in winter de-icing the air stone will give maximum water turnover for ice reduction.