Sound attenuator, английский In ductwork, a device (usually prefabricated) especially designed to provide much greater sound attenuation than would be provided by an equal length of ductwork; the pressure drop through the device is greater than for an equal length of ductwork.
Mousehole, английский Same as rathole or dilly hole, except that the hole is for the purpose of holding a length of drill pipe or rod instead of a kelly
