Courtesy of CZ and their reference library, we are looking at a prototype model of the vz.70 pistol intended to use a suppressor. It has an extended and threaded (with interrupted threads for quick attach/detach) barrel, and a mechanism to allow for locking the slide. This will prevent the slide from cycling, thus reducing the noise of a shot and also preventing the ejection of spent brass. Ultimately only a handful of these were made, and they never got into production or issued use.