peg, tuning peg = stroik, klucz (na gryfie gitary, skrzypiec)

Guitar String Tuning Peg

Source: http://www.dhgate.com/product/guitar-string-tuning-peg-tuner-machine-head/148832109.html

stroik, klucz (na gryfie gitary, skrzypiec)

peg , tuning peg = stroik, klucz (na gryfie gitary, skrzypiec)

English sentence and Polish translation

If you fix the peg, the guitar should be playing. = Jeżeli naprawisz stroik, powinno dać się grać na tej gitarze.