Another way to save on purchasing CO2 airsoft sound grenades and accessories from Hakkotsu as MoaiHobby are having a special offer on the Hakkotsu Thunder B Sound Grenades now. You get to save on getting more from their sound grenade pack, with the shell replacements also at lowered prices. There are different types of these Thunder B Sound Grenades so better hurry and visit the MoaiHobby site before stocks run out.