This is the Ballistic 4.5T 540-Size Hand-Wound Stator from Novak.
FEATURES: Allows changing of turn count of the Novak Ballistic spec brushless
motors
Low-loss solder tabs
INCLUDES: Novak Ballistic 4.5T Stator with instructions
REQUIRES: Removing solder tab and sensor assemblies from motor
SPECS: Turns: 4.5
Size: 540
Outer Diameter: 34.3mm (1.4")
Length: 39.3mm (1.5")