on either side of the locking rod 12 the rolls 38 are arranged with a corresponding fastening are optionally rotatable on the locking rod 12 and are made from plastic material the cupboard side receptacle 40 comprises two hook like elements 41 which are arranged homologously to one another in the form of a double hook on a fastening flange 47 a detachable and displaceable fastening advantageously takes place by fastening elements 49 such as screws in a recess e g a t slot 44 of a vertical hollow section 45 of a frame 46 during the closing or locking process the locking rod 12 passes by a slot like spacing opening 48 of the cupboard side receptacle 40 into the vicinity of the double hook 41 in order to ensure a directed insertion of the locking element 14 upper and lower vertically directed wedge surfaces 42 are formed on the double hook by means of which the rolls 38 of the locking element 15 pass into a locking position in a central area 39 an insertion of the locking elements 14 into a receptacle 40 can be brought about both from above and from below the construction of the double hooks 41 as cupboard side receptacles 40 also makes possible a random left or right side fixing the guide blocks 32 of the rod guide 30 can also be used for left.