A rotatable cutting head for a vegetation cutting device comprises: a rotatable spool having a cutting line wound thereon, a free end of the cutting line being arranged to exit the cutting head via an opening. A cap comprises a feeding mechanism, the feeding mechanism comprising a peg for engaging with the spool and configured to allow the spool to rotate relative to the cutting head and feed cutting line from the spool when the free end is short than a predetermined length. A moveable locking mechanism is configured to move between a locking position in which the locking mechanism engages the cutting line feeding mechanism and limits relative movement between the cutting head and the spool land a release position in which the locking mechanism does not engage the cutting line feeding mechanism； The cutting head comprises a spool comprising: a central portion for receiving the cutting line wound thereon； a flange connected at one end of the central portion. The flange comprises an internal track on a base of the flange configured to guide the peg of a feeding mechanism in the cap, the internal track comprising at least one notch for engaging the peg and preventing relative motion between the cutting head and the spool. At least one external camming surface is on a peripheral edge of the flange. The camming surface is configured to engage with the moveable locking mechanism as the spool rotates relative to the cutting head and cause the moveable locking mechanism to move between the release position and the locked position.
