Related Clues:

• Beer-keg adjunct
• Listen in, in a way
• Keg add-on
• Snooping aid
• Beer barrel poker?
• Anxious foot action
• Plant a bug
• Send a telegram
• Furtive listening device
• Hidden mike, slangily
• It may be barbed
• "This is Spinal ___"
• Begin to use
• Surveillance option
• Audible dance style