The Hakkatsu Thunder B Sound Distraction Device line is a system designed to replicate the flash bang style grenades used by the military and law enforcement agencies around the world. The core is a reusable cylinder in which a standard 12g Co2 cartridge is punctured to release an approximately 130db explosion. The shells are disposable plastic pieces that split when the Co2 cartridge is punctured and expands. The Co2 is punctured by pulling a pin and dropping a spoon similar to the real deal! I offer replacement shells as well.
This is a package that gives you 12 replacement shells if you need to restock and still have your core.
Note that quality on the Valken Thunder V compared to the Hakkatsu Thunder B are very comparable and they are compatible with one another. You should not see any difference between the two visually and in use.