Lowest price ever according Camelcamelcamel. Comes to $11.48 per (one)blade. This is the 360 replacement head which has more flex than the original blade. Model QP440/50
According to the Philips website, the 360 head fits on all Oneblade models.
Mod 18/7: Available again and price drop from $45.91 to $44.38.
I'm guessing these don't work on the original one blade base?