Assuming that I'm using the Bracers of Flying Daggers magic item (from Waterdeep: Dragon Heist, p. 190):
This armband appears to have thin daggers strapped to it. As an action, you can pull up to two magic daggers from the bracer and immediately hurl them, making a ranged attack with each dagger. A dagger vanishes if you don't hurl it right away, and the daggers disappear right after they hit or miss. The bracer never runs out of daggers.
I'm hidden from the creature I want to attack, so I have advantage on attack rolls against him.
Analyzing the item wording, it seems that the two daggers are meant to be thrown at the same time, one for each hand. To sustain this idea, there's the fact that you can't move between those two attacks.
My question is this:
Would I apply advantage from being hidden on both the attacks?