There are quite a few choices to make when you buy an Octo.
Of course a major consideration is always the price.
As with the Regulators, you can also get Balanced or Unbalanced Octos.

Because they are only ever used as a backup, majority go for the unbalanced as it is cheap and simple.

The 4 main types of different Octos are described below:


The first is an Octo attached to your BC hose.  This saves an extra hose from the first stage but has three disadvantages:

  1. It makes a big “block” on the left hand side and makes dumping the air awkward.
  2. It requires a non standard hose to provide the high volume of air. This means your reg won’t work with any other BC.
  3. In an emergency you need to give up the primary on a short hose and breathe off the BC octo, not ideal to say the least.

Not recommended.


 This is a simple unbalanced octo on a long hose.
Does the job.

No nonsense and a good choice.

Will require more frequent adjustment if you have a balanced primary.


  The advantage of these is that they are ……well small and compact. Very nice to dive with.

They also work up side down, but the quality is a bit cheapish, the covers tend to break over the long term.  But there are plenty of spares.


  This is the ultimate!

The right hand hose means it does not have to curve, it is immediately in the correct position.
This is a top of the line balanced Octo, so breathes exceptionally well and in addition lasts a lot longer before services.
Adjustable means that it can be “de-tuned” for normal use and then opened up for emergencies. Prevents the octo free flowing.
It is essential to use a balanced octo with an “overbalanced” first stage (one with an environmental sealing system) Unbalanced will free flow at depth.