A Gun-Microphone assembly consists of a gun and microphone together. A gun generates a pressure pulse. A microphone converts acoustic pressure pulses into an electrical signal. The gun and microphone are normally supplied together as a unit. The gun generates a single pressure pulse which travel down the casing annulus gas and is reflected by collars and the liquid level. The reflected pressure waves deflect the microphone and generate an electrical signal. The electrical signal is fed to the computerized Well Analyzer. The well head attachments are rated from 0-15000 psi