Knit Picks Options Interchangeable Knitting Needles:
The smooth cable join lets your stitches slide around your knitting needles with no snags while the long threaded join ensures that your cables and knitting needle tips stay securely in place.  Additionally, the flexible emerald cable has very little memory so you can start knitting immediately. Simply unscrew the needle tips and screw on the cable caps to keep your knitting safe when your needle tips are required elsewhere. Lace knitters will love that they can tie a piece of scrap yarn through the tiny hole in the cable end (used for the tightening key) and thread a lifeline through their lacework at regular intervals while they are knitting.

Includes one cable, 2 end caps and one cable key, for use with Interchangeable Needle Tips (not included). 
Note: Length of interchangeable cables refers to the total length achieved when the needles tips are attached.