38mm XXXX-Fast/RFF-Fast Speed High Performance Nozzle requires the use of the Bell Divergent and does not require the use of a Nozzle Washer as the Bell acts as a Nozzle Washer and Motor Divergent. This more than double the surface area exiting the Nozzle and I looks Cool To. This part is Hard Coat Anodized to take the abuse of motor operation. Ensure that your fin design or recovery system protects this on landing. CAUTION THIS IS NOT A STANDARD MOTOR. WE WILL SHREAD YOUR ROCKET OR DRIVE THE MOTOR THROUGH YOUR ROCKET ONLY SERIOUS SPEED FREAKS WHO ARE ROCKET SCIENTIST SHOULD EVEN ATEMPT TO FLY.