The G&G 14mm CCW Adaptor - 12mm inner to 14mm outer is available for purchase from several online airsoft retailers. This adapter allows you to attach most standard 14mm CCW threaded accessories, like suppressors or tracer units, to airsoft guns with 12mm CCW inner (female) threads. 
 
Construction: The adapter features a durable full-metal construction, typically aluminum alloy.
Compatibility: It is designed to fit the G&G Piranha MK1 and Piranha SL GBB Pistol Series, as well as the G&G GPM92 and GTP9 models, and any other airsoft gun with an internally threaded 12mm CCW barrel.
Function: It converts the 12mm CCW inner (female) threads of the airsoft gun's barrel to a more common 14mm CCW outer (male) thread, offering greater customization options.