Possible Clues:

• Signal increaser
• Device increasing loudness
• Pair filmed briefly moving part of roadie’s kit?
• Intercom component
• Electronic equipment to increase signal strength
• Uses it to clearly broadcast a British politician gets life over mid-air racism initially
• Device that strengthens mint imperial, strong to eat
• A PA will require some gain from this
• Loudspeaker driver
• Device augmenting sound