Why does the Viewsonic VX3211-mh monitor have some sort of pin on the back?

Question

Monitors

I bought a 32 "monitor here. I'm glad. But there was a pin in the kit, the purpose of which remained unclear to me.
There is not a word about it in the instructions. Strong, heavy (a lot of metal inside), 65mm in length. At first I made sure that it was excellent screwed into the VESA mounting holes.Then I saw in the picture that it is screwed in behind near the very edge.There is a hole for it only on one side (on the left, when viewed from the side of the screen)
.Why is it needed?

Answer 1

Hang headphones if there is an audio output nearby.