This is the Xnova Lightning 4025-1120KV 1.5Y Brushless Motor with a 6mm "Type B" 28mm Shaft. The "Lightning Series" was developed from the extremely successful XTS Platform. Lightning series motors are simply the pinnacle of performance, and efficiency. If you're looking for the absolute best brushless motor within the Xnova line up, this is what you're looking for! This high performance brushless motor was developed 520-600mm size helicopters when powered with 6S.