This post is for those that have wondered about knitting two socks at the same time. This will work doing two sleeves at the same time as well.
There are two balls of yarn. You can use both ends, but I just found it easier to use two seperate balls. Yes they do get tangled. The most dificult so far is casting on, and then moving the yarn so they follow the same direction. My ribbing is K2P1.
When you look closer, one of the two circulars has an orange color. I used a Sharpie to color one of the two so that I can tell them apart. This helps to tell the two needles apart, and easier to know which side you are knitting.