This Harken Laser Outhaul Clew Hook is a part of the full Clew Hook and Block system.
You may need to leverage open the loop end of the hook to be able to insert the loop end of the 16mm block (Block sold separately). We have found this to be very easy. Run the outhaul line and tie the clew tie-down-line as usual.
Comes with a length of line for securing to the boom.