Polyester strings are infamous for 2 things:

1. extreme stiffness
2. losing tension

Then came along Isospeed Cream! The industry also stopped calling polyester, “polyester” and gave it a new name: “co-poly”. That’s because they claimed they added other ingredients that they couldn’t simply call it polyester. Also, 1st generation polyester strings were insanely stiff and unforgiving. I dunno. I’m not a chemical engineer. But I have worked in journalism and the photography/film world for years to know a stragetic rebrand when I see it. 

Cream was one of the first soft “co-polys” that had about the same stiffness as a “synthetic gut” and was the best at holding its tension (only lost about 25% of tension vs 40-60% loss from many early polys). These 2 things were unheard of in the polyester world. I personally think it was a game changer for those who were about to say goodbye to polyesters. I was one of them.

I also think it’s one of the more powerful polyesters out there. Now, mind you, it is still a polyester and only lasts for 3-8hrs for me in the mains and crosses but when it’s fresh OMG it plays so nicely! Don’t worry, when it’s used as a cross string, it lasts MUCH longer. I primarily use it as a cross string in my hybrids for this reason.