Pony Fixed Circular Knitting Needles come in Aluminum for sizes 2.25mm - 7mm, and a more lightweight plastic for sizes 8mm - 25mm. Use these needles for flat knitting: at the end of each row, just switch the needles around as you would with normal straight needles. Your project sits in your lap as you work, instead of hanging off the needles - much easier for larger, heavier projects. Circular needles also allow you to knit 'tube' projects, like socks, cowls and hats, in the round. Please note that the options given represent the length from needle tip to tip and not the cable itself.