armband vs water wing

armband

noun
  • An inflatable band worn round the arms to keep afloat in water 

  • A band worn around the arm of the captain of a team. 

  • A band worn around the arm, usually to symbolize protest or mourning. 

water wing

noun
  • One of a pair of inflatable plastic bands, normally worn on the upper arms, to help a wearer float in water and learn to swim. 

How often have the words armband and water wing occurred in a corpus of books? (source: Google Ngram Viewer )