This is the B4-2 Standard Model Rocket Engines/Motors from Estes. Suitable for Ages 10 & Older with Adult Supervision for Those Under 12. FEATURES: Single stage engine Standard engine designed for flights in rockets weighing less than 4 ounces, including the engine Engines tested and certified by the NAR Easy to use and comes with clear instructions INCLUDES: Three B4-2 Engines Three Igniters Four Igniter Plugs REQUIRES: Model rocket Adult Supervision for Children Under 12 SPECS: Length: 2.75" (7cm) Diameter: .69" (18mm) COMMENTS: WARNING: Flammable. Read instructions before use Do not burn, soak in water to destroy Due to small parts that could cause a choking hazard please keep away from children 3 years of age and younger For your safety and enjoyment, always follow the NAR Model Rocketry Safety Code while participating in any model rocketry activities Residents of California, New Jersey, Rhode Island and North Dakota please review the Terms of Sale for state specific restrictions Estes products may contain chemicals known to the State of California to cause cancer, birth defects or other reproductive harm sdw 6/22/01 ir/jl updated tlc 12/13/12