user19706: Few days ago, one of my opponent wore Bose anti noise earpieces. Of course, I didn't call the referee cause I knew that it wasn't a cheat technique. But I was wondering what is the rules for that kind of object. I think that some players could confuse with earphones and call referee for cheat attempt.
Thank you for your answers :)

user4418: 
But I was wondering what is the rules for that kind of object.

Strictly speaking they are not allowed without the arbiter's permission.
This is what the latest FIDE Laws of Chess state:

11.3.2.1 During a game, a player is forbidden to have any electronic device not specifically approved by the arbiter in the playing venue.
However, the regulations of an event may allow such devices to be
  stored in a player’s bag, provided the device is completely switched
  off. This bag must be placed as agreed with the arbiter. Both players
  are forbidden to use this bag without permission of the arbiter.
11.3.2.2 If it is evident that a player has such a device on their person in the playing venue, the player shall lose the game. The
  opponent shall win. The regulations of an event may specify a
  different, less severe, penalty.


19706: <p>Few days ago, one of my opponent wore Bose anti noise earpieces. Of course, I didn't call the referee cause I knew that it wasn't a cheat technique. But I was wondering what is the rules for that kind of object. I think that some players could confuse with earphones and call referee for cheat attempt.
Thank you for your answers :)</p>
 4418: <blockquote>
  <p>But I was wondering what is the rules for that kind of object.</p>
</blockquote>

<p>Strictly speaking they are not allowed without the arbiter's permission.</p>

<p>This is what the latest <a href="https://www.fide.com/component/handbook/?id=208&amp;view=article" rel="nofollow noreferrer">FIDE Laws of Chess</a> state:</p>

<blockquote>
  <p>11.3.2.1 During a game, a player is forbidden to have any electronic device not specifically approved by the arbiter in the playing venue.</p>
  
  <p>However, the regulations of an event may allow such devices to be
  stored in a player’s bag, provided the device is completely switched
  off. This bag must be placed as agreed with the arbiter. Both players
  are forbidden to use this bag without permission of the arbiter.</p>
  
  <p>11.3.2.2 If it is evident that a player has such a device on their person in the playing venue, the player shall lose the game. The
  opponent shall win. The regulations of an event may specify a
  different, less severe, penalty.</p>
</blockquote>
