Two simple steps to transform a standard engine into a D size. Insert a standard engine into the adapter, and insert the adapter into a rocket. 3 adapters per pack. Reusable.Standard to D Engine Adapter toStandard to D Engine Adapter

Estes model rocketry is recommended for ages 10 and up with adult supervision for those under 12. Unless otherwise specified, all models require assembly. Tools, construction and finishing supplies sold separately. In order to launch, a launch system, model rocket engines, starters and recovery wadding are required - sold separately-unless otherwise specified.