Anti-Dry-Running Level Protection direct from Wanlin Fire Protection — 12-year factory experience, NB-IoT Submersible Liquid Level Transmitter (WL-LT400) certified CE/FCC/RoHS/ISO9001. Key specs: NB-IoT wireless, IP68 waterproof, anti-corrosion, sewage-ready, 0-50m range. MOQ 200pcs, OEM/ODM available.