This is a dummy silencer made by Alloy Empire in China for their 1/2 scale Sig Sauer P226 semi-automatic pistols. 4 3/16″ long including the threads. I believe the threads are Metric 7, and you will have to have the proper tap to tap the muzzle of the barrel to install. The base that threads into the muzzle is solid. The rest of the silencer is hollow, & has a hole in the muzzle end for appearances. The silencer looks to be made of aluminum with a black anodized finish. These might also work on some other 1/2 scale miniature rifles, pistols, or machine guns. See also the dummy silencers for the Alloy Empire Beretta M92 pistols, which have a smaller M6 thread. Several available. Price: $25.00.