Backfire 120mm MO Wheels Set fit Zealot X and S2 Series, including 44T Pulley Set and 280mm Belts.
The bearings inside the Backfire 120 MO Wheels are special 26*8*8mm bearings, so traditional skateboard 608 bearings do not fit the wheels.
For people who want to use Backfire 120 MO wheels on Hammer Sledge ( with 10mm truck axle), you can swap the bearings to the 6000 bearings, plus the 320mm belts.
Please follow the Halo Remote Pairing Parameters below after you install the new wheels.
In addition, please remove the plastic piece from the motor cover to get enough clearance for the bigger wheels. 
