Fretboard Markers Inlay Sticker Decals for Guitar - Caduceus Set You can install these on your electric or acoustic guitar with 24 3/4h, 25 1/2h guitar necks with 22 or 24 frets. it's possible lemon oil or finger ease spray using it after you installed. Fret Marker could cover original dot marks easily. They will not get caught by your fingers while playing! Material is PET