Harken's furling swivel works in conjunction with a furling drum to allow the trailerable cruising or dinghy sailor to set and furl the jib from the cockpit. An optional hoistable ball bearing halyard swivel can be installed on your headstay allowing you to raise or lower the sail without removing the headstay, and to tension the luff separately from the mast rake. The 3mm low-load swivel is for use with furling drum 163. Both parts together form furling kit 434. Harken Small Boat units are for furling only, not reefing.