The Opening Size of Each Wrench Is Adjustable Within the Range of 19-51mm(3/4-2"), 32-76mm(1¼-3"), 51-121mm(2-4¾"), and 115-170mm(4½-67/10"), Which Is Ideal for Turning Nut or Bolt. Adjustable Opening Size: the Opening Size of Each Wrench Is Adjustable Within the Range of 19-51mm(3/4-2"), 32-76mm(1¼-3"), 51-121mm(2-4¾"), and 115-170mm(4½-6. ).