A 1/4 inch jack, also known as a 6.35 mm jack, is a type of audio connector commonly used in various audio equipment. It features a cylindrical shape and is designed to connect devices like guitars, amplifiers, and headphones. The size refers to the diameter of the plug, which is 1/4 inch wide. This jack can come in two main types: mono and stereo. A mono jack carries a single audio channel, while a stereo jack transmits two channels, allowing for a richer sound experience. The 1/4 inch jack is popular in both professional and consumer audio applications.