Pack of three Estes B4-4 model rocket engines, designed for small to medium rockets and tested by the National Association of Rocketry. Each engine provides a reliable boost and a 4-second delay for recovery deployment, and the pack includes igniters and starter plugs for convenient launches. Ideal for beginners and experienced hobbyists seeking consistent mid-range performance and dependable ignition. Warning: Product is flammable, use caution and follow Estes safety guidelines. Includes three Estes B4-4 model rocket engines with igniters and starter plugs - tested by the National Association of Rocketry, designed for small to medium rockets, balanced thrust with a 4-second delay, requires B-class rocket equipment, flammable - follow safety instructions.