The present invention relates to a sole made from a first material, at least one receptacle made from a second material, and at least one stud, which can be releasably mounted within the receptacle by inserting a fastening projection of the stud into the receptacle. The fastening projection includes a first locking member, and the receptacle includes a flexible wall having a second locking member. The flexible wall is deflected when the fastening projection is inserted into the receptacle until the first and the second locking members engage.