What is behind the Duke's ear when he looks back at Paul right before applying seal to accept emperor's request to rule?

Question

In 2021 Dune movie at the 10:11 mark, the Duke looks back at Paul and has something gold looking under his ear stuck to his skin. What is it?

Answer 1

Called a "servo-receiver"

A reddit post has the same conversation, extracts are from this below:

Thufir uses it in the ornithopter when they are cleared for take off, and again when they are viewing the spice silos and he's notified that Duncan has arrived.

From: https://allnovel.net/dune-dune-chronicles-1/page-29.html

"The Emperor stood in front of his throne, right hand pressed to right ear, the servo-receiver there chattering it's report on the situation."

The Children of Dune mentions a Sardaukar using some sorts of implants behind his ears and in his throat in order to communicate with the HQ.

see Thufir receiving messages on it at least two times: to fly to the palace with Jessica and Paul, and when showing the spice cannisters to Leto, when Duncan returns; then Leto using it to call guards while roaming in the darkness.

Its a servo-receiver. a simple communication device mentioned in passing at the end of the first book

it seems a very direct illustration from page to screen, the position of the device at the right ear, pressing it with the hand to admit communication, and even the chattering sound it emits all match.

Also appeared in the original Dune:

From: Glossary of Dune (franchise) terminology

Servo-receiver – A communications device worn in the ear. In Dune, Shaddam wears one during the Battle of Arrakeen to receive updates on the battle.

Answer 2

It's a communications device, similar to a bone-conductor device, such as this one. .

The servo-receiver is supposed to be worn in the ear, and this one is behind the ear. I can't remember the exact same device in the original books. I think this design is Villeneuve's vision of the kind of earplug used to communicate.

Here are screenshots of Thufir Hawat wearing and using such a device to communicate.