Farsan 6mm Red Shell for 0521 MAD MAX Double Barrel Shotgun 
 
Only For Hawsan Double Barrel Gas Shotgun
Gas Power
6mm x 6 BBs Per Shell
Lightweight and features a removable bottom portion for gas fillin
The lower portion is sealed using an O ring and can be removed by simply pulling it apart.  Some force is needed but not so much where it feels as if you need a tool.