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.
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%.
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.
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.
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.
