Grub cap as shown, applicable to certain KWC blowback models.

Manufactured for mould-cast plastic w/ two-point retained hexagonal cut-out for use in conjunction w/ the allen key that came standard w/ the KWC pistol in question.

Thread: M21 x 1.25 x 9 male, compatible w/ 6.5mm hex drive / allen key. Has galvinized iron insert specifically for that, however, this insert is only two-point retained and is usually replaced because that iron insert comes loose. This can be fixed by supergluing them (the perpendicular corner that the iron piece and the plastic shares) together by applying it all along in that corner full circle, though just mind your fingers when using superglue!

The threading is cast moulded plastic and therefore, if not threaded correctly, can strip / camout easily. Make sure the cap basis is parallel to the base of the magazine prior to threading in, to prevent cross-threading, especially since the threading is plastic.