The player was to use the Parabolic Microphone in the cut mission named Parabolic to gather enemy intel in the level. They would have to gather intel from sentries on a bridge, a sentry on his phone, and from an officer on the river bank. They would later have to save a hostage. The weapon itself is referred to as "parabolic", and the models for it are missing. The sprint key would be used to target and amplify conversations. This, like many other non-harmful utilities, were included in a canceled mission. This proves that the final version of Call of Duty 4: Modern Warfare was intended purely to be shooter gameplay, which is further reinforced by the lack of cutscenes.
The Parabolic Microphone appears as an attachment in Call of Duty: Advanced Warfare, enabling suppressed gunfire to be seen on the minimap. Enemies firing suppressed weapons will appear as a red circle, differentiating it from standard red dots. It can be attached to all primary weapons except the Blunderbuss, NA-45, Heavy Shield and MDL, and it is also available for the Atlas 45 and MP443 Grach pistols.