This is the C11-3 Standard Model Rocket Engines/Motors from Estes.
Suitable for Ages 10 & Older with Adult Supervision for Those Under 12.
Single stage engine
Standard engine designed for flights in rockets weighing less
than 6 ounces, including the engine
Engines tested and certified by the NAR
Easy to use and comes with clear instructions
Two C11-3 Engines
Adult Supervision for Children Under 12
Length: 2.75" (7cm)
Diameter: .95" (24mm)