Now in 4.5mm/.177 BB Firing MK2 NBB Pistol is the development model of the original MK1 NBB Pistol. MK2 has the new designed outlook with metal outer barrel for keeping this old-school pistol more modern. MK2 comes with a fiber front sight which  allows user to aim target more faster than using the original iron sights, and the metal barrel makes the weight more balance in order to ensure good handling. Although MK2 is powered by CO2, it can use the gas magazine for KJ Works MK1.