The crab wrench is used to tighten and loosen bicycle BB (bottom bracket) nuts and boss free lids, etc.
Insert the pin into the cutout or hole of the nut to secure it (rotated).
Variable to fit many sizes.
Pin size: φ2.8mm
Pin spacing: 0.4 - 2.2 inches (10 - 55 mm)
Total Length: 6.1 inches (155 mm)
Weight: 2.8 oz (80 g).