what length are the cables in this set?

The cables are 5”, 6” and 8” - one of each length - creating 9” thru 14” circulars. The cables are very thin.

Does anyone know the difference between the red & blue sets?

Hi, The red set contains tip sizes US-000 through US-3. These tips have the Mini (M) join connection. The blue set contains tip sizes US-4 through US-8. These tips have the Small (S) join connection. I hope this helps and thank you for asking. Handsome Fibers.

I don't suppose they be interchangeable with knitters pride cords?

None of the Chiaogoo needle tips will work directly with Knitter's Pride cords, regardless of size. They're fundamentally completely incompatible. Knitter's Pride cords have a protruding screw at each end of the cable, and that fits into a socket set into the needle tips. Chiaogoo puts the screw on the end of the needle tips and the socket on the ends of the cables. If you try to pair a Chiaogoo needle tip with a KP cord (whether Knitter's Pride or Knit Picks) you'll end up with two screws and nowhere to put either of them. Although both brands have adapters available to join one cable to another and those could, in theory, join one cable to something-else-with-the-same-end-as-a-cable, it looks like the sizes are also very wrong. I no longer have the KP adapter, but I have ones for the Chiaogoo small and large cables. The L adapter is too big, and the S adapter is too small. This kit uses an even smaller-than-Small "Mini" socket. Since the KP screw end is already larger than the Chiaogoo S, it would be far too big for the Chiaogoo Mini. (The Mini cords that come with this kit are thinner and much more flexible than other Chiaogoo cords, though! They're more pliable than even KP cords, to the point of being a bit floppy. If it's only distaste for stiff Chiaogoo Twist cords that worries you, rather than a perfectly rational fear of taking up collecting a second (third, fourth, whatever, don't look at me like that!) brand of ICNs, you might be very pleased with this set anyway.)

Can the cords be used with the regular lace tips?

Hello, The cables in this set are the Mini Twist cables. They can only be used with 4 and 5 inch Twist tip sizes US-000 through US-1.5. Thank you for checking. Tracy, Handsome Fibers.