The Oxygen regulator is made by Sherman, the brand speaks for itself, it's quality and reliability is well known among welding specialists.
 
The regulator allows to decrease a pressure of a gas coming from a bottle to desired level. The outer pressure level can be maintained regardless of spikes and falls of input gas pressure. The regulator is equipped with a safety valve, if the pressure excess safe level, it is released outside.
 
More technical information can be found on the right hand side