Original Oclean replacement heads from the PW - Whitening and Cleaning - series, soft bristles, hardness 5 out of 10. For users with sensitive teeth, whitening needs or cavities. Designed for all Oclean toothbrush models - X, X Pro, Elite, F1, Air2, One, Z1. The number 09 in the name only indicates the colour of the head, all PW heads are identical. One piece in the package.