It ensures that the lid fits correctly onto the blender bowl.
Designed for Blender from the series produced after week 6 of the year 2018: - High Speed KB702, KB703 - Ultrablend BL935, LM935 - Ultrablend+ BL936, LM936
* Your Blender's date of manufacture is indicated underneath the product in the form of a four-figure code. The first two figures correspond to the week and the last two figures to the year. E.g. 0618 corresponds to week 6 of the year 2018.