|Release date||August 2009|
|Dimensions|| Diameter: 51mm |
|Bearing size||Size A|
|Response system||Flowable Silicone|
The UnKnown features the same bead-blasting, anodizing, and shape as the 5150, but is two and a half grams heavier and has an A-sized bearing. This makes the yo-yo effective for 5A (Freehand). Moreover, it features laser-engraved artwork by IV on the side of the yo-yo.