Rocket Engine Specifications: Diameter Length Total Impulse Propellant Weight Motor Weight Delay Seconds Propellant Type Fits Estes Mount 18 mm 2.75" 5.00 N-sec 8.33 g 21.0 g 4 B Standard Estes-1602 Retail: $9.29 Our Price: Learn about Payment Options | Security | Privacy | Shipping | Our Company. Trademarks property of Centuri Corporation, Custom Rockets, and ToyBiz Inc.