Thel-mar is an environmental services company specializing in the production of the Thel-mar Volumetric Weir, a calibrated measuring device used for determining infiltration in sewer lines and flow rates in pipes. Their weirs feature a 90-degree v-notch for accurate small infiltration flow measurement and a rectangular portion for larger volume flow rates. The company serves municipalities, USDA, USGS, cranberry fields, universities, and commercial/residential developers. Thel-mar's weirs can be customized with optional bubbler tubes for continuous remote monitoring and come in various sizes. They prioritize rugged construction and non-corroding materials for reliability in diverse environmental conditions.