Here is a cutaway side view of the Air Buddy, shown in it's open position, as if a diver were biting gently on the mouthpiece.
You can see that the valve stem is depressed, tilting the valve face away from the valve seat, which allows the air to flow freely from the low pressure hose, through the mouthpiece, and into the mouth of the diver.
Is it different from the old fashioned 2nd stage octopus?
Sure. You have to bite it to make it work. You have to exhale around it instead of through it like you do with a standard regulator. It will take only a few minutes practice until you feel comfortable with it. Learning new skills is what makes us better divers.
To use the old fashioned 2nd stage octopus you need to:
1. Place it properly in your mouth (it is odd shaped).
2. Either press the purge button with your hand or blow into it to force the air out of the pressure chamber. If your lungs are empty, you will need to push the purge button.
3. Suck to get your air supply.
To use the Air Buddy octopus you need to:
1. Place it in your mouth. It will position itself correctly.
2. Bite and breathe.
There is not enough water in it to require purging and you don't need to use your hands to make it work. That could mean the difference between life and death.
You don't have to suck the air as you do with an old fashioned 2nd stage. The Air Buddy will flood your mouth with air. All you have to do is breathe.
And, you are only going to use it as an air source during that short amount of time that it takes to get you back safely to the surface.
Try this experiment.
Place your thumb in your mouth just far enough so your center teeth come down on the thumbnail.
It doesn't matter whether whether your nail is on the top or bottom.
Now bite gently until you can feel a little pressure on your nail. That's all there is to it. If that were an Air Buddy in your mouth, you would have air flooding your mouth. When you release the pressure, you stop the air.
Don't seal your mouth around your thumb. Allow enough space so you can breathe in and out with your thumb in place. That's how you hold the Air Buddy. If you are pressing it, the air from the Air Buddy will force all the water out of your mouth and will come bubbling out around your thumb. When you want to exhale, your exhaled air will also go out around your thumb.
It should take you all of about three or four minutes of practice to become proficient in this new skill. Once you can do it, you will realize how much easier and faster and safer it is than using the old 2nd stage octopus.
Let's discuss it further.
Up until now, every safe diver carried an extra regulator 2nd stage hanging from his first stage, to be used by his buddy if he ran out of air. It was a good idea when it first started.
The double hose regulator was a good idea, originally, but it was replaced by the single hose regulator.
The horse collar life vest with the little C02 cartridge was a good idea, but it was replaced by the buoyancy compensator. The C02 cartridge was eliminated because it was actually a safety hazard.
Using an extra 2nd stage as an octopus was a good idea at the time because there was nothing else.
Here's what's wrong with using an extra regulator 2nd stage as an octopus:
It has to be cleared before you can breathe from it.
If you carry it attached to your BCD it is cumbersome and gets in the way.
If you tuck it inside your pocket, it is a real nuisance because of its size, and it is not easy to get out in a hurry.
If you leave it hanging behind you, it can get hung up on coral, monofiliment line, nets, various underwater obstructions, and It can get filled with mud or sand.
It is an inconvenient source of air for filling other flotation items.
It needs periodic maintenance by a trained technician to keep it operating.
It may cause the diver to mistakenly submerge with his/her pony bottle regulator instead of the primary regulator in the mouth at the start of a dive, with dangerous consequences.
The Air Buddy solves all that because:
It is virtually the same size as the hose on which it is mounted, or it eliminates the hose completely.
It is a Positive Pressure Air Supply (PPAS). As soon as you bite it you are supplied with all the air you need.
It won't get hung up on fishing line, coral, nets, anchor lines, other divers, etc.
It does not need any more maintenance than your dive knife.
It doesn't take up any room in your BCD pocket.
It can be tucked into almost anyplace on your gear.
It can be passed through a tiny opening to give an air supply to someone being rescued.
It only takes a squeeze of your fingers to use it to fill lift bags.
It can be used to easily put air into the BCD of a diver who is out of air.
It can never be mistaken for the normal second stage, even in zero visibility.
It is the safest source of emergency air now available.