Knitters Pride Interchangeable Black Cord Variety Pack includes 6 Common Sizes: 16, 24, 32, 40, 47, 60. These flexible cords lay flat, with no kink or twist, making them easy to store. The long threaded screw-in “join” insures that cord and needles stay connected. Tightening hole provided in the metal join for extra secure tightening and a specially designed “key” facilitates effortless tightening.