|Release date||June 2007|
|Dimensions||Diameter: 53mm |
|Material||Plastic with Heavy Gravity rims|
|Bearing size||Size C YYJ Large|
|Response system||Hybrid starburst/O-ring|
The YoYoJam K-OS is Eric Koloski's signature series yo-yo, released in June 2007. The K-OS (pronounced "Chaos") has a shape similar to that of the Dark Magic, with a smaller diameter and flatter rims for snap starts and chopsticks-style tricks. It uses Heavy Gravity material for rim weighting, much like yo-yos such as the SpinFaktor HG and the Copperhead.
Its successor model, the K-OS Extreme, would be the last YoYoJam product to use the Heavy Gravity material before its discontinuation.