Reinforced QD gearbox frame V.2 + spring guide
Gearbox frame for ??MP5, M4, M16, G3, etc.. The holes for the bearings have a diameter of 8 mm, and the stainless steel bearings are included. The package also include metal spring guide with the bearing. An interesting feature of this gearbox is hot swappable springs. The spring guide can be unlocked by turning in locks and slides out. Spring guide is of course metal.