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Dive Gear Shopping for Dummies: the regulator

regulator diving dive gear
Owning your own reg increases safety and comfort

Your scuba regulator is a big investment; probably the most expensive piece of dive equipment you will buy and certainly the most important! So it’s important to know what you want/need before buying. We’ve written this post to guide you through the options and to understand what the varieties are and how they differ

What is a regulator?

When we talk about the regulator, we refer to the entire delivery system. It is the most important piece of diving equipment, as it allows the diver to breathe underwater. The components that make up the regulator are:

  • First Stage – the main 'hub'

  • Second Stage – where the diver breathes from

  • Alternate air source – or 'octopus' for your buddy in an emergency

  • Low Pressure Inflator Hose (LPI) – attaches to the BCD and usually comes with purchase of a BCD, but can be purchased separately.

  • Console/SPG (submersible pressure gauge) - provides information to the diver

When buying a regulator, while it is possible to buy a package deal, each piece is commonly sold separately. This means you can mix and match between both models and/or brands finding the best for your needs.

The first stage of a dive regulator

regulator first stage dive gear
Yoke and DIN first stages

The first stage attaches to the cylinder and does the job of reducing the pressure in the tank (200 bar) to an intermediate pressure (about 10 bar). The first stage has several different variants:


Much like how different countries use different plug and socket types, the first stage has two different fitting options; DIN or Yoke (A-clamp/INT). The ‘yoke’ design has the o-ring in the tank, whereas the ‘DIN’ has the o-ring in the regulator. A DIN regulator screws into a DIN tank valve and a yoke regulator attaches to yoke tank valve.

scuba tank valve
Yoke vs DIN tank valve

The yoke design was the standard for diving from the beginning, however, the DIN design, which was originally designed for technical divers is beginning to become more popular around the world. This is because the DIN screws in directly to the tank valve providing a more stable and secure connection according to many.

Connection options for DIN and Yoke fittings:

Adapters can be used for both, so you need not worry about your choice but the easiest option is to buy a simple adaptor for the DIN regulator allowing it to fit on either tank valve.

adapter regulator DIN Yoke
Adaptable tank valve or DIN reg adapter for Yoke

1. An insert can be used in a DIN tank for fitting a Yoke regulator

2. A Yoke attachment can be screwed onto the DIN regulator to fit onto a yoke tank.


This is the way the first stage reduces that tank pressure and there are two choices here; the piston or the diaphragm. A piston regulator is less protected from the elements; water enters the first stage and presses on a piston, so less suited to cold water diving but better for depth – the more depth, the more pressure will be applied to the piston. There is only one moving part so it can also be easier to service. The diaphragm regulator works with a lever pushing against a membrane in an air space and is better protected from the elements. The diaphragm regulator is generally better for cold diving, however, there are more moving parts making it more complex to service. Realistically, it plays a small part in your decision and the differences will be minor unless you are a real techy!

An added option is to buy a regulator with an Environmental Seal. This means the first stage is protected against the elements, and will not freeze up if diving in cold water.


This is where your budget will come into play. The most basic option here is called an unbalanced regulator. This means it is affected by the water pressure; breathing resistance will increase as pressure (depth) increases, but also as the gas in your cylinder decreases. Then there is the balanced regulator, here the regulator compensates for the change in pressure, meaning there will be no change in breathing resistance as pressure changes.

The other option, favored by technical or deep divers, is the overbalanced regulator. These increase the flow as the pressure increases, making it easier to breathe at depth. They are, however, therefore more prone to free-flow, which may be off-putting as a newer diver.


The first stage is where all the hoses are attached via the ‘ports’. A standard regulator will have 1 or 2 high-pressure ports and 3 or 4 low-pressure ports. The low-pressure ports are for the 2nd stage, alternate and the inflator hose. If you dive drysuit, you will require an extra low-pressure port for connection to inflate the dry suit. The high-pressure ports are for the pressure gauge or ‘console’ so will need at least one. If you use a transmitter for your computer, it would be best to have an extra port. Simply put, the more you spend, the more ports you will have.

The second stage of a dive regulator

second stage regulator dive gear
second stage

The second stage (and alternate) reduces the intermediate pressure (from the first stage) to atmospheric pressure and is what you breathe through.

Here again, there are a couple of different options. Some regulators will have an adjustable knob, which allows the diver to adjust ease of breathing and some will boast more comfortable mouthpieces, however, these can be bought separately at relatively low cost. Mouthpieces are easy to buy and come in standard fit, comfort/orthodontic mouthpiece, or even mouldable mouthpieces; no one is better and is an entirely diver preference.

alternate air source dive gear
Alternate air source

The alternate or octopus, is the same as the second stage but is there for your buddy in case of an out-of-air emergency. For this reason, they are often brightly colored, usually yellow, and have a longer hose.

The console

The console provides the information, namely the SPG (submersible pressure gauge).

dive gauges console
Consoles for SPGs, depth gauges, compas, computer...

The SPG measures how much gas is in the cylinder and can be either digital or manual and measure gas in either bar or PSI. It can be bought as a single console with SPG only or added options include a depth gauge and/or compass. This again is diver preference, some divers prefer a wrist-mounted compass leaving less on the console and others like to have everything in one place. Simply put, the more gadgets on the console, the more you will pay!

To sum up...

Unbalanced Airflow affected by pressure or

Balanced / Over Balanced Better/constant breathing/airflow regardless of depth

DIN - Better for extreme temperature, more secure connection

Yoke - Most common

Piston - simple parts, heavier, better for depth

Diaphragm - more parts, better protected, lighter

Environmental Seal - Protects from matter/water entering, protects against freezing in cold water


Low Pressure - 2nd stage, octo, inflator hose +/- drysuit

High Pressure - console +/- transmitter for computer

We have asked some of our staff what regulators they are using, so you can check some of these options!

Yvonne: Scubapro MK25 / R600

Bastien: Scubapro MK25 / G620

Helene: Aqualung Mikron set

Sammy: Scubapro MK25 / R600

Julia: Aqualung Titan set

Ardi: Aqualung Calypso set

Happy shopping!

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