The Estes A10-0T engine is a booster stage engine designed for model rocket flight and has to be used with a mini engine. This engine is for flights in rockets weighing less than 4 ounces, including the engines.

Each package includes 4 engines, 4 igniters and 4 igniter plugs.

Specs
Motor: A10-0T
Stage Type: Booster
Length: 1.75 in.
Diameter: 0.5 in.