The flame-resistant wadding is required in most Estes rockets unless they are tumble recovery. Recovery wadding is installed in between the motor and the parachute and is designed to prevent damage to the parachute. Plastic parachutes can singe or melt when exposed directly to the ejection charge from the motor, but recovery wadding is designed to take the brunt of that ejection.
Depending on the motor you are using, a few to several sheets are recommended.
Contains 75 sheets, enough for about 18-25 flights and is necessary to launch model rockets.