Compatible with worker 40-darts double row magazine or universal NERF magazine. Two or three groups of flywheel can be triedWhich can effectively enhance muzzle velocity range accuracy. Manufacturered by WORKER. Instruction manual available for reference ATTENTION PLEASE: All the parts are separate you need to install all the parts onto your blaster So make sure you have some modding skills before you buy. you can also buy other parts in our store to to DIY your own blasters. Compatible withGen 3 flywheel chamber cagefor Worker Dominator blaster.