These Sabian tuned bass crotales/cymbal discs are 1-octave in range, C to C. There are 13 discs total. They are tuned one octave lower than the lowest set of Sabian crotales commercially offered. This is an excellent opportunity to extend your crotales set to 3 octaves or more! The discs are tuned A=440 and were made in the 1990s by Sabian as a prototype custom set.