The Air buddy can give you up to 20% more breathing time on your air source than any other alternate air mouthpiece.

How does it do that? 

This next statement is very important to understand. The use of the Air Buddy as an alternate air source mouthpiece will increase the breathing time you will have on any given air source up to 20% more than you would have if you use any other alternate air source mouthpiece available at this time .
The Air Buddy does not increase the amount of air you have left but delivers it to you in a more efficient way so that much less of your oxygen is wasted, allowing you to last longer on that same amount of air.
It will do that whether you are using your Air Buddy mounted on a pony bottle, as an alternate breathing mouthpiece on your BCD or as an octopus coming from the 1st stage of your regulator.
trachea with regulators

Only the Air Buddy starts each breath with completely fresh air


When breathing from a normal regulator 2nd stage, the first air that goes into the lungs is the stale air that is located in your tracheal and oral cavities as well as the chamber of your second stage. This air is high in CO2 because you have just exhaled it.

    Exhaustive testing in hospitals has proven that the best way to keep oxygen levels up and CO2 levels down is to deliver the gas to the patient in a the form of a puff bolus rather than on simple demand.

     1. The trigger that signals your body to take a breath is the amount of CO2 in your blood.
When your blood carbon dioxide level reaches a certain level, your body takes a breath. You don't have anything to do with it.
     2. When you exhale, the air that remains in the space from the opening to your lungs up through your throat and mouth and including the air in your regulator second stage pressure chamber is  high in carbon dioxide.
     3. When you take your next breath, you suck air through your regulator and the first air that goes into your lungs is that exhaled stale air that is already high in carbon dioxide.


No CO2 in Air Buddy

The Air Buddy is a one way upstream valve which means it cannot free flow and never has any CO2 build-up in it.

A normal 2nd stage regulator is a two way downstream valve which means a high pressure leak or valve malfunction can cause it to free flow and it will retain an amount of CO2 build up depending on its physical size.

air space
Let's say you have switched to your alternate air source which happens to be a common 2nd stage regulator octopus or one of the new alternate air source systems built into the power inflator of a buoyancy compensator. If you have enough air to last, at your normal rate of breathing, 10 minutes, that same amount of air can last 12 minutes if you were using an Air Buddy.
Would that extra 2 minutes be useful?  Maybe you wouldn't need it. 
Maybe it would make the difference between surviving or not.

How does the Air Buddy do this?

You need to know a few facts to understand how this happens.
The Air Buddy doesn't work that way.

     1. You don't suck to get air from an Air Buddy. You squeeze the mouthpiece and the Air Buddy blows the air into your mouth.
     2. The air that is blown in is fresh air, with no carbon dioxide.  There is no stale air in the Air Buddy itself because you never exhale into it. All the air space in an Air Buddy is fresh air.  That fresh air creates a turbulence, mixing whatever stale air you have retained in your oral cavity and trachea, reducing the percentage of carbon dioxide. So the air that you are inhaling into your lungs has less carbon dioxide than what you would get from any other alternate air source system. This is the same type of system used to give breathing air to premature babies in the hospital for their well being.
     3. So, each breath you take with an Air Buddy has less carbon dioxide in it, causing your body to wait for a longer period of time before your carbon dioxide level builds to a point where it triggers your breathing response.
      4. The net result is that your body will automatically take only 4 breaths using an Air Buddy during the same time period it would be taking 5 breaths with any other current system.
      5. This difference in breathing is controlled by your autonomic nervous system and is not even noticed by you that it is happening.

      It's one more safety factor to have on your side.