The Laser Marked Model 102 Water Level Indicator is designed to accurately measure groundwater levels in small diameter applications. The Solinst Model 102 Water Level Meter uses a 10mm (0.375") probe that is constructed of stainless steel and includes 10 weights for use in greater depths. A braided copper outer conductor gives flexibility and a stranded stainless steel central conductor gives strength. It is easy to repair and splice. The cable jacket is of heavy-duty polyethylene for durability.