A diving regulator used for scuba diving is a demand valve system that reduces pressurised breathing gas from a scuba cylinder through two stages to ambient pressure and delivers it to the diver when they inhale. 

High-quality regulators that provides smooth, easy breathing whether you are at 5 metres or 50 metres are a critical part of any diver's gear setup, it's what's keeping you alive.

Most divers prefer to own their own regulator as you are trusting your life with them and so you want to know that they are in good working order, comfortable to use and familiar with any features they have.

When choosing a set of regulators, be sure they have all of the features that you need.  Cheaper regulators are made of lesser quality materials and have less features, they may do the job but certainly won't last as long as higher quality regulator brands. 

So choose smart and buy once.