Koleston Root Call.

Hair grows roughly 1.25 cm a month. Between days 25 and 32 after coloring, the root starts showing. Koleston Root Call is the first hair-color box that knows: a small QR inside the pack pings the buyer between day 25 and 32 — "the root is calling, time to plan the next one." Behavioural data, not retouched manifestos.