This is a Dimensions kit and they use their own thread, so you are not able to purchase it separately. The only way to replace the thread is to contact Dimensions directly and tell them you came up short on thread. Their contact information should be included with your kit.

and GOOD LUCK!

I have some Dimensions thread that I have saved. If you post the color numbers, I can see if I have the threads. I too ran short on Dimensions kits and other threads I had extra. Trying to match up the colors is rough.

I too have extra floss. Post your color numbers and we will see if they match. Also tell us if you only need a little or a lot. I keep all my Dimension left-over thread, some a lot, some only a strand or two. If you are contacting Dimensions, it can take quite a while to get the flose, if at all.
Adele