Battlemaster's AudacityFollow

I was thinking of buying the Battlemaster's Audacity. I'm not 100% clear how it works. Does it work like a healing potion where you gain an increase in health plus a boost in maximum health for 15sec? Then after 15s you lose only the max health bonus? Or does it only give you a bonus in max health for 15s?

I am pretty sure the OP meant when this trinket is used and you get the increased health, and at the end of that 15 sec duration do you lose the HP gained. For example, if you have 2000/10000 HP and use this trinket you will end up with 3750/11750 HP. Then you get hit for 3k to put you at 750/11750 HP. Now once the 15sec of the trinket wears off are you dead, or do you retain the HP the trinket "healed" you for?

I have never bothered getting the trinket because I have always assumed that you have to "repay" the gained HP at the end of the duration (similar to warrior's laststand ability?). Correct me if I am wrong.

It works like last stand does on warriors. You use it, your max and current hp go up by 1750, then when the effect is done, your current and max hp drop by 1750.
If the -1750 hp would have killed you, it drops you down to 1 hp.
Great trinket for arenas :).