15cm I bought these as a spare pair for the summer. I hardly wore them because it was a barefoot childcare period. I put a name sticker on the heel and then peeled it off. I've uploaded photos, and they show that it peeled off cleanly. They have been opened, and the inspection was done by an amateur. They are not completely unused. Please check the condition in the photos. I will ship them using the cheapest method. Please be aware of this as well.