Facnor Block 2 to 1 Option Often high halyard loads are required to properly sail with Code Zeros so Facnor offers many variations of 2 to 1 fittings. Compact sheaves integrated into the halyard swivel reduce weight aloft and increase luff length while a block installed on the bottom of the drum can reduce the amount of mast compression. Many options are available to accommodate any specific need. Block Model Suitable Furler FB60 FX 2500 FB70 FX 4500 FB90 FX 7000 FB110 FX 12000 FB130 FX 20000