Hornwall's Horn (active against sirens) (The Witcher 3: Wild Hunt)

Too bad it doesn't work on harpies.

And then why crossbow?

the crossbow knocks down 1, and the horn of all at once in the area

very useful thing has slept more than once

and this is its console code ('q202_navigator_horn')

Video of the location where Hornwalle's Horn was found. Improved quality as requested

Clay man
I remember that the horn is on the island with the giant. You show the place where the nest of monsters and the stone of power is, is there another one or what?