Inside the case are needle tips (the white sticks) in the following U.S. sizes: 5, 6, 7, 8, 9, 10, 10 1/2, 11, 13 & 15. The blue cables also come in different lengths, the largest of which is missing, because I'm currently using it.
To use, select the tips you want, the length of cable you want, and insert the little black tip of the cable into the end opposite the tip of the needle. Give it a quarter turn to lock it into place,
and you're set to go. The separate cables can be joined to each other.
There are six cables and two "extenders" which are the little black sticks at the bottom right hand side. They hook two cables together. I also have the Companion Set of 6 more cords in length from 5" to 19" and two more extenders.
The round, black objects are end buttons. You can store a knitted piece (for example, the back of a sweater) on some cable while you knit the other parts. The end buttons click onto the ends of the cable so the knitting can't slide off.
You know the shawl I showed yesterday? Today, at the beginning of row 25 I decided that the knitted fabric was too loose and open, so I took it off the needles and unraveled the entire piece. Then I cast on again and started over with U.S. size 9 needles instead of the #11's the pattern called for. The shawl will not be 28" in length when finished, but I'm much happier with what is being produced. It's also much easier to see the pattern developing, which helps me know where I am in the right side rows. The wrong side rows are easy: knit 1, purl to the last stitch, knit 1. Here's a sample row from the right side: Row 23: Knit 1, [Knit 2 together] twice, [yarn over, knit in the front and back of stitch] 3 times, yarn over, [slip, slip, knit] twice; repeat from the beginning 7 more times, knit 1.
That, actually, is a translation of: *K1, [k2tog]twice, [yo, Kfb] 3 times, yo, [ssk] twice; rep from * 7 times more, k1 - 121 sts. If you lose your place in the middle of the row, you realize it at the end, when you have extra stitches or not enough stitches. At that point, you knit backward until you've reached the mistake and then reknit the row. I've lost count of the times I've knit backward and reknit. It doesn't bear thinking on. But it's the only way to achieve a fine finished project!