Harken 4:1/3:1 mainsheet system.

This 4:1 mainsheet system features two 57 mm Carbo fiddle blocks with high-load ball bearings for low-friction operation. A pivoting lead block mounted on the boom directly above the trimmer provides powerful two-handed sheeting. The new carbo blocks save weight over the classic versions, but either can be used. You can also splice a carabiner to the end of your mainsheet and use that for a quick and easy connection to the becket on 2622. In light air, disconnect from the becket and let the carabiner run to 2621. This makes the mainsheet 3:1 for better light air control. 

To complete the system as pictured you will need the following Harken hardware: