This completely stainless, inline oxygenation system injects oxygen into your wort as it travels from your wort chiller to fermenter and allows you to read the temperature coming out of your wort chiller at the same time. It has a 3" Dial Stainless thermometer and a 2 micron diffusion stone. The inlets and outlets are 1/2" barb. The oxygen inlet is 3/8". It is the economical alternative to our completely sanitary, stainless oxygen system, PRO30., ,How long should I apply oxygen while transferring to the fermenter? — We recommend you transfer half of your wort to your fermenter before applying inline oxygen (O2) to your wort transfer. If you apply O2 the whole time while transferring you are wasting O2.