Interchangeable with any Denise knitting or crochet set, needles connect with the Denise locking mechanism. Ten knitting needle sizes: US5/3.75mm, 6/4mm, 7/4.5mm, 8/5mm, 9/5.5mm, 10/6mm, 10.5/6.5mm, 11/8mm, 13/9mm, 15/10mm. Six cords: 5 inch, 9, 12, 14, 16, 19 (13, 23, 30, 36, 41 and 48 cm) for circulars from 17 inches (43 cm). Four end buttons to turn any cord into a stitch holder or to use as an end cap for a straight, flexible needle; two extenders for cord-to-cord connections. Needles are made from plastic resin and are 4 inches (10cm) long for US5-10 ½ and 4.5 inches (11cm) for US11-15. Made in the USA and guaranteed with normal knitting use.