OS RZ buddy. This motor was in my original Mbx4 that I raced back in the day. Took the buggy out after sitting for the past 6 years and broke it after two tanks. Put it in an mbx4RR parts car I bought and broke that due to a faulty servo horn. Retrofitted mbx8 arms on it and bought the truggy. Motor ran so good I threw it in the truggy and bought a 50 dollar sportworks motor and put that in my RR. That motor is a beast as well. Looking forward to see the RZ throw the truggy around. Love that OS engine.