A few curling shoe models, e.g. BP's 400, have the front slider not completely glued to the shoe.
The back part of the slider stands away from the sole.
That is no production problem, this is a hinged sole.
It keeps a much larger part of the slider in contact with the ice even when the foot is bended.
Very important: the sole is as reliable as the traditional, completely glued slider. Years of experience tell us, that the understandable fear, the sole might fall off, does not materialize.
This feature was first used in top models like the BalancePlus Delux or the Ultima Dress.
Today this invention is also available in the medium class.
Here is our blog article with more details, a picture and a video:
Skeki explains: what is a hinged sole?