Flash Hiders, Faux Suppressors, Tracer Units, and misc Barrel Extensions for airsoft guns. Suppressors / Silencers are for looks only and non-functioning. Tracer units work with glow in the dark BBs for a laser gun like-effect. Most barrels use reverse threads (unscrew the opposite direction as normal) called CCW. Most take 14mm size. But be warned, some weird guns like G&P and others use CW, so it's traditionally threaded as normal.
Flash Hiders, Suppressors, Tracer Units
PTS M4SD-K Mock Suppressor
PDI SPR Flash Hider for VSR-10
PDI Rebar Cutter Flash Hider
Laylax Quick Muzzle Fitting 14mm CCW