The 493 Underdeck furler lowers tack height, maximizing sail area. A ball bearing swivel on the headstay, allows you to raise/lower the jib or adjust luff tension. The jib halyard exits the mast and attaches to a 40 mm 2621 Carbo fiddle; the control line leads through a 40 mm 2148 T2™ Loop block and adjusts using a 396 29 mm Carbo Pivoting Lead block with Carbo-Cam.