Voltcraft lwt 01 automatic temperature compensating conductivity meter voltcraft lwt 01 the voltcraft lwt 01 measures conductance due to total dissolved solids tds of aqueous media it can be used to check purified water or water quality in aquariums highly accurate due to its automatic temperature compensation function supplied with calibrating solution 1430 micro s cm 1 x 9v battery pack calibrating screwdriver storage box and operating instructions voltcraft lwt 01 atc conductivity