Compact (4" × 6" × 3 1?2"1 1?2 lb.) facilitates placing the unit on an operating table or mounting to wall or to anesthesia machine with accessory brackets for unmatched convenience. Greater sensitivity enabling use with chest piece cups at weaker signal sites, as well as with esophageal stethoscope tubes. Miniaturized sensor unit suitable for direct connections to accessory sound sources with less clutter. Mode selector switch for choosing best audibility characteristics for the type of monitoring desired. Pulselite flashing red light indicator for visual heart/pulse monitoring. Metal case seamless, deepdrawn, heavy aluminum case with carrying handle provides complete shielding from pick up of electrical interference from other equipment.