Bicycle trailer connector material stuff or replacement?

I have a pacific trailer with roll bars and I really like the thing at times. I have a strange connector though that looks like licorice in a spring. Thicker like a cigar made of teflon or rubber perhaps.

Does anybody know where I can obtain a coupler of this nature or what the material is called? Teflon rope or plastic rope.. Kevlar?

Thanks in advance! Would like to keep one or two in the tool pouch (100 pound crate).. lol

I have found these that may prove useful or faulty to others here.. Please let me know what you think.

http://www.midwestcontrol.com/series.php?id=17

I had an old BMP friction kit that had a steel frame and welded a real car trailer to that.. Had some weight and the clutch drum broke and I could never find a replacement that would fit.

Hey all.. I might have stumbled on a fix or even a possible connector replacement!!!

Heavy duty super hard 1/2 - 3/4" Firefighers rope!! Cut into small sections, drill, seal hole with heat or glue perhaps or both.. Poke small bolt through and let it hang!! I imagine one could use 2 of these and have added support!

I love stumbling. GLTA