Sensors for measuring distance, chemical levels in aqueous solutions, not for medical use; Digital pH meters; Water testing instrumentation for monitoring and detecting contamination; Scientific instrumentation for measuring concentrations of chemicals in water; Electronic apparatus for testing the electrical conductivity of medical hydrogel electrodes; Flowmeters; Liquid level sensors; Electronic-based instruments for measuring environmental parameters including humidity, mold, bacteria, air quality and water quality; Saccharometers; Electronic apparatus for use in the treatment of aqueous systems, namely, for analysis of the system conditions for the purpose of applying the appropriate chemical treatment; Electric, electronic, or electrochemical oxygen monitors and sensors for environmental use; Monitoring devices for the aquaculture industry used to monitor dissolved oxygen and temperature; Scientific instrumentation for measuring weight, chemical levels in water,