Designed for performance racing and cruising sailors, MKIV furling systems are strong, lightweight and aerodynamic, with the performance and features Harken is known for: longevity, ease of use, and simplicity of installation. These free-rolling systems make all the difference in headsail control, allowing racers and cruisers to quickly furl and reef while maintaining great sail shape and optimal speed. Smoothly unfurl your headsail instead of hoisting a large genoa in light air. Drum installs over existing turnbuckle and is adaptable to a variety of rigging options. Toggle assemby accepts standard turnbuckle using swage, rod, Norseman, or Sta-Lok terminals connect Rotates around rod or wire headstay so furler bearings don't carry the headstay load Multiple rows of Torlon ball bearings help minimize friction for smooth furling Double foil grooves allow for fast hoists, douses and sail changes Independent swivels furl sail center before head and tack for improved sail shape and smoother furling Easy installation; this unit is designed for owner installation Unit comes standard with 38'7" of foil. If your headstay is longer, an extra foil can be ordered for a maximum headstay length of 45'7" Seven-year limited warranty