Harken roller furlers have recently gone thru a design change.  Chose a MKIV for offshore use or the Cruising version for coastal applications.  The new style Harken furler uses a standard turnbuckle for stay length adjustment.  The turnbuckle attaches to a link/toggle assembly that is specific to each size of furler.  What this means is that if your current head stay is fairly new and the turnbuckle is most of the way open these units can be installed with out head stay modification in most cases.  Harken has a MAP pricing policy but you can check out our selling price using our new shop on line feature listed in the index on the left, call us, or send an e-mail.  The site is under construction so you'll need to use the search function and type in the part number listed below than add the part to your basket.