Engines for model rocket 3 – E12-6 Engines 4 – Starters 4 – Plugs The Estes E12-6 engine is a 24mm diameter upper stage engine designed for model rocket flight. This engine can also be used as a single stage engine. Maximum lift weight is 14 ounces. Each package includes 3 engines, 4 starters and 4 starter plugs. ATTENTION: Additional Hazardous Materials shipping and handling charge of $35.49 will be applied at checkout. ATTENTION: These engines cannot be sent to post office boxes. Please be sure to provide a PHYSICAL ADDRESS when purchasing E and F sized engines. Warning This warning applies to all Estes manufactured model rocket engines. This product can expose you to chemicals including crystalline silica, which is known to the State of California to cause cancer, and birth defects or other reproductive harm.