This is Novak's Ballistic Spec Hand-Wound Stators -- 8.5T-21.5T (#S6608-#S6621).
Each Ballistic motor features interchangeable wound stator construction. By unscrewing the main screws, the motors’ solder tab and sensor assemblies can be easily removed to leave only the stator, which can be replaced with many different motor wind options. These replaceable hand-wound stators create countless racing options for racers looking for a cost effective way to change a motor's turn count.
Each kit includes:
One Hand-Wound Stator
Installation Instructions
Kv readings are measured with a standard 12.3mm sintered rotor (Novak #5941).