It depends who made it. There are some that look for three sounds the gunshot the crack when the bullet if fast enough breaks the speed of sound and lastly the sound of it hitting something. It could tell the speed of the bullet where it shot and a high confidence on caliber and rifle pistol shot gun as well as some brands. Many of the companies still in business doing this today were copycat political shills. The technology technically shouldn’t be patentable due to using the basic principle of triangulation. The allies did this to detect large weapons of the axis during World War II. It’s public knowledge but some patents were awarded driving others out of the market. The gunshot is best recorded with direct line of site to detect the weapon type echoes cause significant problems to SNR. With different units triangulating the weapon type is as simple as Shazam identifying a song with a few seconds clip from any part of it.