Dboys M-51 DBAL Battery Box which also included a high output 1100mAh 10.8 Volt mini custom Ni-MH battery pack. The battery box is more compact that most on the market, making it a great choice for all airsoft guns, especially smaller ones where space might be an issue. Battery box mounts to any standard Weaver or Picatinney rail.*Note: Be sure to use only approved Ni-MH battery chargers to charge the included battery. We are not responsible to damage to battery due to improper charging.