The fret collar kit has all the tools you need for quick and effective fret polishing without having to spend time taping off your fretboard. Simply place the fret collar over each fret and polish using the included fret polishing cloth (Also sold separately). this process removes corrosion buildup to reveal a slick, shiny surface. Dunlop fret collars are made of flexible steel to accommodate various radius measurements. Includes two different sizes to fit most Fretted instruments.