The PT30 is a Pressure Transducer for 30 PSI measurements with Extech Models SDL700 Pressure Meter/Datalogger and 407495 Heavy Duty Pressure Meter with Interchangeable Transducers. For air or non-corrosive/non-ionized gas. 1/4” PS, 19 teeth per inch with 3.9ft/1.2m cable.