Insert
From PyroGuide
An insert or garniture is a device, small or large, put into shells as an additional effect or as the main effect.
Examples:
Whistling devices
Small shells
Shell of shells is a shell that only contains a lot of smaller shells inside. It gives the illusion that nothing happened, and then the sky erupts in a cascade of multicoloured small shells.
A Beraq shell is a Maltese style shell which contains a great number of small salute inserts with different delays.
