mõõtevahend muda- ja settetaseme mõõtmiseks veekogudes, veehoidlates, mahutites jne, depth meter is specially designed to measure the interface for sludge, it could be continual and online to monitor the sludge interface level in the sewage wastewater treatment field, level meter that detects sedimented or thickened sludge at various positions in waste water treatment plants