A guitar tuner is a device that helps the user ensure that each of a guitar's strings are playing the right pitch. There are many different types of guitar tuners, from pitch pipes to advanced electronic devices.
A pitch pipe is a basic type of guitar tuner. The person tuning the guitar blows into the pipe to hear the pitch, then adjusts the tuning peg to match the pitch. There are many guitar-tuning websites that mimic the function of a pitch pipe.
Vibration tuners, which clip on to the head of a guitar, are ideal for loud environments. The tuner senses the pitch through vibrations and tells the user how close the string is to playing the correct pitch. Other types of guitar tuners include strobe and microphone tuners.