A scuba regulator is probably the most vital part of your scuba equipment

Of course it is an integral part of your scuba gear and the scuba regulator is useless without most of the scuba diving equipment – the point is though – if your regulator fails you are definitely going to have a problem.

Of all your scuba diving equipment, this is the item I would say it isn’t worth trying to go cheap. If you buy a good one, and then maintain it well, it will last you a lot longer than any of the other scuba gear you buy.

The scuba regulator consists of:

  • A first Stage
  • A second stage
  • Octo or Octopus
  • Inflator hose
  • Pressure gauge hose

First Stage.

The first stage comes in two types

DINS – which is a lot less common and screws directly into the outlet valve on the Scuba cylinder.

When you go to a dive centre they will ask you if you need an ‘insert’ this is an adaptor which is used to adapt the cylinder for an ‘A-Clamp’ fitting.

Many experienced divers will tell you DINS scuba regulator first stage is the better fitting – I think it is slightly less common but a valid point is that it is less likely to ‘blow’ an ‘O-Ring’. This is when the air pressure foirces the rubber seal out and then air begins to escape at a very loud as well as high rate. When it happens it can give you quite a fright!!

While I think of it – you will often see divers setting up their gear, then having opened up the air from their cylinder, bend down and listen for leaking air – DON’T DO THIS! If the ‘O-Ring’ blows while you are bent down listening, your ear drum is probably going to be history……..

The first stage acts to reduce the air pressure from the cylinder, which can be as much as 300 bars to ambient air pressure to allow you to breath without getting your lungs blown out!

There is a mechanism inside consisting of usually a diaphragm.

These pictures are to give you an idea of why I havent gone into much detail as to how exactly they work - first, it is quite a complicated piece of equipment - and secondly, I don't really know how it works! The air is directed to a series of ports which are where the additional equipment like inflator hose to your BCD, pressure gauge and dive computer are attached.

Second Stage

This is the part of the regulator which runs to your mouth.

It consists of a pressure hose, a mechanism (surprisingly enough!) which allows one way flow of air, exhaust valve for breathing out (and believe it or not if you get sick – all that will pass through safely), a mouthpiece (very necessary) and a purge valve – you will learn some diving skills using the purge valve in your open water training.


The Octo is a spare regulator, purely for emergency use, either you have a problem with your second stage, or a dive buddy runs out of air and will pair with you to use your air supply whilst you both make a controlled ascent. It is often coloured bright yellow and has a longer hose to enable easy use by another diver. It is constructed in exactly the same way as your second stage, quite often you will find it isn’t a good a grade model as the second stage.

Air 2

I have what is called an ‘Air 2’ which is a regulator combined with the inflator hose – it just makes your equipment more streamlined and one less hose to worry about catching on wrecks or reefs…..

Ok - thats about all I have to say about a scuba regulator.

Deal with a reputable Dive centre and they will be able to give all the good advice you need.

Scuba regulator experts now! Click to go back to Scuba Equipment page

Scuba Diving Magazine has some reviews of regulators new on the market this year - click here.

Contact us

Home page