Metal outer barrel for electric guns. Length 13 cm. One end with outer and second end inner thread. Both 14mm counter clockwise. Any compensator, flashhider or silencer fit on this barrel extension. Visually intended for weapons M4, but the barrel can be screwed to most other weapons. For example, G36, AK, P90, MP5, SCAR ... etc.
Total part length is 13 cm. It extend your barrel at 11.8 cm.
