Hooksmart.
Hooksmart is a device (patented) which allows the hook onto a sail in automatically. With this device eliminates the halyard elongation under load and reduces the load on the mast compression. This has a great advantage when using sails as the code 0, with Hooksmart is possible, to equal mast load, twice the loads into the luff line and eliminate the stretch of the halyard, obtaining a perfect luff. 

Hooksmart for the mainsail
It is possible to use Hooksmart for the mainsail without any change on the mast. 

For further information, please download the technical sheet.