A4479 - 25MM HT BLK: 25mm Single Shackle Head Wire BlockPart # = A4479 Description = Single + Shackle Sheave Dia (mm) = 25 Length (mm) = 41 Line Dia (mm) = 2 5 Shackle Pin (mm) = 5 Breaking Load (kg) = 750 Weight (g) = 33 25mm Single Shackle Head Wire Block. Specifically intended for use where wire lines are subjected to low running speeds and higher static loads. Shackle Head When the shackle and small axle are removed from the head of the block the two side plates are free to swivel. This allows easy