any experience with cortland climax 7x tippet?

I only have experience with one spool but it was such crap I would not
want to spend my money on another one. I sent an email to Spirit River
who distributes it and they said they would contact Cortland.

My spool which was brand new shipped from spirit river had several week
spots. Now I know what you are thinking, "hey, its 7x tippet, of course
it will break easily". Well on the non defective parts, if I pulled on
the line with my wrists locked, only pulling with my fingers, I could
not break the tippet. But several times when tightening a knot, with my
wrists locked (since it is so light) the line would break, and not at
the knot. This has happened over 6 times and I have not even used the
full 30 meter spool.