The addi Turbo Circular stitch holder allows you to knit off of your work and hold it on the lockable stitch holder, until you are ready to use it again. When you"re ready to pick up your project again, simply knit back onto your needles. Sizes are listed in approximate US sizes -AND- exact metric sizes for your convenience. All addi knitting needles are manufactured to exact metric sizes. Please Note: Every addi product purchased from an Authorized addi Dealer comes with a Lifetime Warranty from any manufacturer"s defect.