These shorter, four inch tips are part of the interchangeable knitting needle system by HiyaHiya. The stainless steel tips are smooth and slick, and have a special, sharper point that is ideal for intricate stitch manipulation. These are not complete needles, you need to attach them to cords to create circular needles. They will only interchange and attach to cords made by HiyaHiya. Be sure to purchase the correct size cords for the needles you choose. Small cords connect to needle sizes US 2-8 (2.75mm-5mm), which large cords connect to needle sizes US 9-15 (5.5mm-10mm).