Original Oclean replacement heads from the PW bleach and cleaning series with soft bristles, hardness 5 from 10. For users with sensitive teeth, tooth whitening needs or decay teeth. Designed for all OCLEAN toothbrush models - X, X Pro, Elite, F1, Air2, One, Z1. The number 09 in its name indicates only the color of the head, all PW heads are the same. There are two pieces in the package.