The Estes B6-2 engine is single stage engine designed for model rocket flight. This engine is a standard engine designed for flights in rockets weighing less than 4.5 ounces including the engine. Brand Name: Estes Product Type: Model Rocket Engines Color: Brown Number of Pieces: 3 pc Number in Package: 1 pk Length: 3 in. Recommended Age: 10+ yr Thrust Duration: 0.80 sec Max Lift Weight: 4.5 oz. Max Thrust: 2.7 lb. Diameter: 1 in. Propellant Weight: 0.23 oz. Time Delay: 2 sec Total Impulse: 5.00 N-sec Model Number: B6-2 Engines Weight: 0.61 oz.