The 16" cables are green and all other sizes are black.
These cables work with the Knit Picks Interchangeable tips. Both the short and regular length tips fit on these cables, but you must use the short tips for the 16" cables. This is because the circumference is too small to allow for the longer length of the regular tips.
Each pack comes with one cable, two stopper ends and a key to tighten the tips to the cable. Don't worry if you loose the key, a safety pin or a needle will do the job too. The stopper ends can be twisted on to hold your stitches while you use your needle tips for another project which means you only ever have to buy each needle size once! The cables are also great for using as stitch holders (16" is a great size for this).
Always check which size and length needle your pattern calls for. In general:
16" cables are great for working small project in the round, like hats, baby sweaters and sleeves.
24" cables are usually suitable for cowls, sweater yokes or children's garments.
32" and 40" are most commonly used for sweaters, shawls or blankets.
If you need a longer length than 40" check out the cable connectors which you can use to connect multiple cables to create any length you like.