My mechanics tells me that this is one of the popular high speed bearing used by Yamaha 125Z/R owners to add more performance to their bike. Other than SKF, there are FAG and NSK high speed bearing. Usually SKF and FAG are more expensive than NSK due to their durability and ability to stand high strain and pressure of the high speed engine load.
This high speed bearing from SKF is a good addition to the new gearset that you have like the Yoshi Racing Engine Gear Set or IKK Racing Engine Gear Set.

The item is available for sale here