Estes E9-4 Engine Pack (3 Engines)Estes E9 4 Model Rocket Engine Pack Each package includes 3 engines, 3 starters and 4 starter plugs This is a pack of three Estes E9 4 Rocket Engines. The Estes E9 4 engine is a single stage engine designed for flights in rockets weighing less than 15 ounces, including the engine. Each package includes 3 engines, 3 starters and 4 starter plugs. Specifications: Engine Type: E9 4 Total Impulse (N sec): 30. 00 Time Delay (Sec): 4 Max Lift Weight (oz g):