Possible Clues:

• Accessory for a pilot or telemarketer
• A gamer may talk into one
• Receiver covering ears
• Advertisement brought in these unusual phones?
• Piece of equipment for a telemarketer
• Leader placed cans
• Piece of live-stream gaming equipment
• Sound equipment fitted over the ears
• Cans provided by principal teacher with group
• Twitch streamer's purchase that might look like cat ears