For the knitters who want it all and more... addi brings you individual pairs of Turbo interchangeable needle tips! Add these US Size 6 (4.00 mm) to your existing Click set for more project potential, or take the plunge and begin building a set if you haven't already! Click Tips require no tools to change; simply insert the cord into the tip, twist and release. The tips will remain secure until you change them. Click Tips are nickel plated by way of an electrostatic process, which produces a smooth, rounded edge, where the tip and the cord "click" together.