This is usually known as a shotgun or rifle mic because of its similarity in
appearance to a gun barrel.
The slots in the barrel allow off-axis sound to cancel giving a highly directional
The longer the mic, the more directional it is.
The sound quality of these microphones is inferior to normal mics so they are
only used out of necessity.
A close relation of the interference tube microphone is the parabolic reflector
This looks like a satellite dish antenna and is used for recording wildlife
noises, and at sports events to capture comments from the pitch.