This set includes 9 guitar fingerboard radius measuring rulers with specifications of 18.41 cm, 24.13 cm, 25.4 cm, 30.48 cm, 35.56 cm, 38.1 cm, 40.64 cm, 43.18 cm, and 50.8 cm radius. These rulers are used for repairing and adjusting guitar, bass, and ukulele fingerboards.