Designed for headsails such as gennakers, screechers, code zeros or even staysails. Just roll them up and drop them down. Large diameter (7.5 in) sheave for handling sails in demanding conditions. Heavy duty sealed thrust bearings in a sealed housing ensure no corrosion problems. Designed for a continuous drive line so you never run out of line when rolling up your sail. Precision machined from billet aluminum for strength and light weight. Simple, no maintenance, line guide allows easy line changes. For sailboats to 48 feet. Top-rated by Practical Sailor.