A close cousin of the SpinFaktor HG and the Copperhead, the K-OS features rim weighting like YoYoJam's composite body models, but was an all plastic model. The rim plastic was made much denser than the rest of the yo-yo by adding heavier particles to the mix. It is also a slightly undersized model.
The K-OS (pronounced Chaos) is the signature model of Eric Koloski and is one of the rarer of the yoyojam releases. I believe only one run was done, and then it was no longer produced.
