Each needle size has its own color for easy identification.
3 cable needles in US sizes 3 (3.25 mm), 6 (4 mm), and 9 (5.5 mm)
The longest (green) is approximately 4 1/8 inches long.
The middle (purple) is approximately 3 3/8 inches long.
The shortest (blue) is approximately 3 1/8 inches long.