Who makes it has no need for it. Who buys it has no use for it.who usesitcan neither see it or feel it. What is it?

https://www.google.com/search?source=hp&ei=O1wsWsSgNcTHjwSX-YnoAQ&q=Who+makes+it+has+no+need+for+it.+Who+buys+it+has+no+use+for+it.who+usesitcan+neither+see+it+or+feel+it.+What+is+it%3F&oq=Who+makes+it+has+no+need+for+it.+Who+buys+it+has+no+use+for+it.who+usesitcan+neither+see+it+or+feel+it.+What+is+it%3F&gs_l=psy-ab.3...3728.3728.0.5216.1.1.0.0.0.0.0.0..0.0....0...1c.1.64.psy-ab..1.0.0....0.5tci-huFTa8