armfloat vs water wing

armfloat

noun
  • An inflatable plastic band, normally worn on the upper arm, to help a wearer float in water and learn to swim. 

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 armfloat and water wing occurred in a corpus of books? (source: Google Ngram Viewer )