9 Instruments and Equipment Used in Subterranean Drilling-Namely, Subsurface Recording Pressure Gauges, Formation Testing Pressure Gauges, Thermometer Elements, Subsurface Samplers, Recording Apparatus in the Nature of Coated Metal Shim Stock for Recording Pressure and Temperature; Optical Scanning Readers, Subsurface Recording Instruments, Subsurface Running Cases, Instrument Carrying Cases, Pipe Gauges, and Oil Well Surveying Instruments and Subsurface Gauge Clocks Contained in Surface Recording Instrument