This is the Xnova 4035-600KV Brushless Motor with a 6mm "Type A" 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 for 520-600mm when using 12s LiPo.