This Harken 096 Upright Lead Block is often used to lead spinnaker pole lift, cunningham, outhaul, and other control lines from the mast base.
Harken designed their low-friction Bullet Blocks to lead control lines aft, but these truly Classic blocks can be found in an endless variety of applications. with free-running ball bearings that roll on flat races with minimal friction. They deliver dependable fast trim and release under high or low loads.