Attention Please: There are certain technical thresholds for the use of this product, please confirm whether it is suitable for use before taking the order. This product does not accept returns and exchanges caused by non-quality problems. If you buy this product, it is deemed to be aware of and confirmed to use. It is forbidden to carry out the sealing test with positive or negative pressure, otherwise, it may cause problems such as water leakage in the line, we will not be responsible for this issue. This product is an underwater brushless thruster, which needs to be driven and controlled by an ESC. When the power is high, heat dissipation is required, otherwise, the overheating protection of the ESC may cause the motor to slow down or stop. This issue cannot be considered a quality issue. Description: Item Brand:QX motor Item Name:Brushless motor Material:Metal Color:Black Product Size:About 27.7*61.03mm,blade diameter is 60mm,shaft diameter is 4mm Product Weight:About 118g Compatible Models:Nest boats, trawlers, unmanned boats, school model teams, DIY models Specification: Model:QC2221-380KV/550KV No.f.Cells:3-6S Lipo Service Voltage:12V-24V No Load RPM:8000-9500rpm Maximum Rated Power:400W Thread Length:90cm Plug Banana Head:3.5mmm Package Included: 1X QC2221 Brushless Motor