This is the F42-4T 29mm x 83mm Single Use Econojet Model Rocket Motor from AeroTech Consumer Aerospace. FEATURES: Blue Thunder- Produces a bright violet-blue flame with a minimum of exhaust smoke These motors provide a higher level of thrust than White Lightning or Black Jack motors of the same total impulse Instruction sheet included INCLUDES: One F42-4T 29mm x 83mm Single Use Econojet Model Rocket Motor SPECS: Propellant type- Blue Thunder Dimensions: 1.125" x 3.283" (29mm x 83mm) Motor weight- 2.7 oz. (77g) Propellant weight - .9oz. (27g) Maximum recommended lift-off weight: 22oz. (620g) tlh 3/15/11