and the ability to use HTC (High Torque Capacity) or LTC (Low Torque Capacity) internal gear sets

and TAM51604 black)

Tread (F/R): 174mm

They've also added in a strengthening rib that extends rearwards

Estes Rockets - E16-4 29mm Model Rocket Engines (2pk) dealslist and the ability to useThe E16 4 Engines (29 mm) by Estes Rockets deliver powerful and reliable performance for mid to high powered model rockets. Ideal for single stage flights or upper stages of multi stage designs, these engines provide an impressive total impulse of 33. 68 N sec and a 4 second delay for optimal parachute deployment. Whether you're launching larger rockets or experimenting with advanced models, the E16 4 is the perfect choice for rocketeers seeking