Rocket Engine Specifications: Diameter Length Total Impulse Propellant Weight Motor Weight Delay Seconds Propellant Type Fits Estes Mount 18 mm 2.75" 2.50 N-sec 3.12 g 17.6 g 5 B Standard Estes 1599Price: $7.85 Sale price: Learn about Payment Options | Security | Privacy | Shipping | Our Company. Trademarks property of Centuri Corporation, Custom Rockets, and ToyBiz Inc.