1st and 2nd stages

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CE mark for cold water

Regsets with a CE cold water certificate have been tested in waters below 10 degrees. When diving in NL/BE this comes in handy. In summer, the water on the surface may be warmer than 10 degrees, however, when decending to greater depths, you’ll hit various thermoclines in which the water temperature may be less than 10 degrees.

1st stage connection

The INT ( yoke) connection uses a clamp type to mount the regulator over the cylinder valve and is tightened into place by screwing the cap. This pushes the first stage into the sealing o-ring of the cylinder valve. With the DIN fitting the male part is screwed into the valve to securely capture the o-ring. We recommend the DIN connection, since this is a safer connection. This connection is mostly used for 300bar cylinders. However, the DIN300 bar connection also works with a 200bar tank valve

1st stage HP port

A second high pressure port on a 1st stage is necesarry if you are contemplating to dive with a computer that is air integrated. The transmitter will be attached to the second high pressure port so that you will always have backup analogue SPG.

Hose type

Flex hoses are, as the word already describes it, more flexible than rubber hoses. By using these types of hoses the chance of your 2nd stage fitting more comfortable in your mouth, is doubled. The flex hoses are also easier to roll up for transportation and a little lighter than rubber hoses.

Nitrox

In Europe, it is mandatory to have a special M26 regset and cylinder when diving with Nitrox. The regsets that are shown here, do not have this special M26 thread. However, these are all technically fit to dive with Nitrox up to 40%. Outside of Europe, you can use these regs to dive with Nitrox up to 40%.

1st stage ACD

Several regset manufactured by Aqualung have the ACD system. This system makes sure that water will not get in to the 1st stage after diving or even if you have forgotten to put on your dust cap when you rinse your materials.

1st stage air supply

When you dive with an unbalanced 1st stage, breathing may become a little harder as your cylinder is being depleted of air. A balanced 1st stage will give you an even resistance during your dive, as long as your cylinder contains more than 20 Bar. An overbalanced 1st stage will give you a little more pressure when at depth, which will make breathing at greater depth easier. You will be able to feel the difference from a depth of 20 to 25 meters.

1st stage type

A piston 1st stage is easier to service, since there are less parts. However, a piston 1st stage needs to be serviced earlier than other 1st stages, since the water does get inside the 1st stage. A membrane 1st stage may be less maintanace- sensitive, however, you’ll have to be more precise in adjusting it. If you would like to dive in cold(er) waters, we would recommend a 1st stage with a membrane.

2nd stage venturi regulator

A venturi switch is a + and – switch on the 2nd stages that regulates airflow. When the switch is switched to the -, the 2nd stage will not free flow when entering the water. When it is switched to the +, breathing is easiest.

2nd stage breathing resistance

With an adjustable breathing resistance switch on the 2nd stage you will be able to adjust the flow of air when inhaling. You may experience a free flow with your 2nd stage when doing a drift dive or if there is a strong current. If you would adjust the switch to a higher resistance, then your 2nd stage will not free flow.

2nd stage air supply

A balanced 2ns stage will make inhaling easier than an unbalanced 2nd stage. If you were to use an overbalanced 1st stage then you’ll always have to use a balanced 2nd stage.

EN250A

Regulator sets with an EN250A marking have been tested by breathing simultaniously through the primary 2nd stage and the octopus. This will increase the pressure that is put on the 1st stage and these regsets have passed that specific test. These sets can be used with an octopus up to a depth of 30 meters. Below 30 meters a separate air system with an extra 1st stage is advised.