Interchangeable Needle Tips - Steel - Regular and Sharp Description
HiyaHiya splits their needles between these two screw sizes. Small tips need small cables and large tips require large cords. An adapter is available to use large tips with small cords.
Small Size: US 2 - US 8 / 2.75 / 5 mm
Large Size: US 9 - US 15 / 5.5 mm - 10 mm
Additional tips, cables, and other accessories (including cables to make 60" needles) are sold separately so you can customize your set to suit your exact preferences.