A rotary cutting head (26) system for a vegetation cutting device (10) comprising a cutting filament insert (60) having a cutting filament (28) and an anchor (42) mounted thereto, the anchor having a protruding element (44) a cap (30) comprising a base (36) a peripheral wall (38) having at least one through hole (40) for receiving the cutting filament and a slot (46) mounted on the cap for retaining the protruding element of the anchor wherein when the cutting filament insert is mounted in the cap, the protruding element of the anchor is configured to slide into the slot and to prevent lateral movement of the anchor towards the at least one through hole and to allow the anchor to slide along a path substantially parallel with the axis of rotation (A) of the rotary cutting head (26).
