Extra Breath Snorkel

Why? I can see no advantage to this (very little air) and having a huge air filled snorkel next to my face would annoy me immensely.
There is also the safety aspect; shouldn't you go up instead of trying to extend your dive a little?
If you need to extend your dive in an emergency (getting tangled etc.) why not carry a pony bottle instead?

So basically if I am at 10 m depth and if that device could hold enough air, then filling my lungs at the bottom would cause a nice lung rupture on the way back up if I don't breathe out. But seeing that the volume of air is so small anyways that isn't going to happen, but it also isn't going to give you any benefit. Besides the issue of potentially getting water into that bladder, which you are never going to get out again.

I thought you'd cop some flak, you might want to move on to the next idea, keep trying

This idea is bad on so many levels, must be a joke (?)

Why reinvent the small scubagear (some of the stuff in James Bond movies actually does Xcist)

Besides, if 1 has even 1 Xtra breath, it aint onebreath diving anymore, thus 1 may not spearfish in many countries.

just to add to what was said above, you can't squeeze that bladder hard enough to pump any meaningful amount of air into the reservoir. For sure nothing above 15 psi, your hand simply isn't strong enough. With this, at 10m depth you won't have any positive pressure in the reservoir. Its volume is mighty small to make any difference in bottom time. But perhaps above all, lung barotrauma risk make this device (if it worked) dangerous enough to just outright ban it.

You seem to have the idea that going deeper will increase the pressure in the tank, and therefor need a pressure safety valve. This is all "upside down" and tell me you don't seem to know about the physics in water... Going down will even the inside/outside pressure out to the point where a collapse is your concern. This is not a well thought idea. Sorry.

Also many other aspects are not mentioned. Especially all the dangerous stuff about breathing pressurized gasses.

But keep on being innovative. On a pure "idea" level I like it....

Yes on pure idea level it is somewhat ok, but:

To B able to breath a 1 breath from the bottle 1 would need few liters of compressed air in what ever depth they R &a fine valve or a regulator. That seems like palstic. It would B inconvinient to make strong enough bottle out of plastic (U should B able to calculate the the pressure needed on surface for few liters in what ever depth, if U have atleast highschool fysics mastered. Fe. 30 m =4 bar +the pressure needed to squeeze lets say 10 liters of air for 5 liter breath to 1 liter bottle)

Also there is no reason to attach your MicroScubaGear to snorkel. To mouthpiece yes, but to snorkel no.

For this U might want to study Primus fuelburner &fuelbottle. They have pressurised fuelbottles with pumps &fine valves (get yourwself a Primus omnifuel burner &you can put the kettle on &remember this sillines with a smile, when U get tired with the project)

http://www.spareair.com/
There is the valid solution for Xtra breath

Without knowing how skilled U R in breath hold diving, but even with no scuba Exp the project is hazardous &only slightly interesting.

My suggestions R:

get better in in apnea to catch the sheephead
-dive with some1
-join a club
-practice
-go to courses


But, if U R serious about the project &want to stay alive!:
-earn the money for scubalessons to learn how to release your breath while coming up; a skill not needed while freediving &to learn about nitrogen narcosis, because with Xtra breath it may become a problem (it may become problem even without gear if deep dives R repeated without sufficient surfacetime)
-study (@least) the basics of the scubagear &fysics

Here is an other airhead trying to kill himself.