The K-OS Extreme is YoYoJam's second signature yo-yo for Eric Koloski. Compared to the original, it is 3.5 grams heavier. The K-OS Extreme uses the copper Heavy Gravity material for rim weighting, thus giving them a brown color. Ultimately, it was the final YoYoJam yo-yo to use the Heavy Gravity material. Due to the higher costs of obtaining it, YoYoJam discontinued the HG line, including the SpinFaktor HG, the Copperhead series and the original K-OS. The K-OS Extreme uses the usual hybrid response system, which combines an o-ring and starburst for a unique response, and a large C-bearing.