The system on the market that combines the furling and the locking mechanism in the same unit. The lock works automatically using the halyard to lock and to unlock.
Used for flying sails (such as staysails and gennakers) it replaces the usual block system where luff tension comes from the long 2/1 or 3/1 halyard and a lot of compression in the mast. The system and the sail are locked on the mast and the luff is tensioned from the bottom by a 2/1 or 3/1 purchase placed under the lower part of the furler.
The compression in the mast is minimized and it is possible to use a smaller and lighter halyard as it only carries the weight the sail. Once the system is dropped on deck, these is only the very light hollowed male end remaining on the mast and the furling-lock mechanism is on deck and accessible for maintenance.