Backed by proprietary Swiss sensor technologies and materials, Apera LabSen 821 Glass-body pH Electrode is designed for testing milk, yogurt, cream, jam, sauces, and other protein-containing liquids. Apera LabSen 821 pH electrode adopts a Silver Ion Trap reference system and Protelyte reference solution to prevent the junction from being blocked or contaminated by proteins. LabSen's blue glass membrane has a faster response time, better repeatability, and is built tough, highly resistant to general impact (totally differentiates from the traditional fragile glass bulb membrane). The electrode can be tested in high-temperature samples (up to 225˚F). Housing Material: Lead-free glass; Junction: Ceramic 3; Reference: Silver Ion Trap; Electrolyte: Protelyte; Length: 120mm; Diameter: 12mm; Membrane Shape: hemispherical; Range: 0-14 pH; Temp. Range: -5 to 100?C (23 to 212˚F); Connector: BNC/RCA; Cable: 3 Ft; Compatible Apera Instruments' meters: SX811-DP, MP511, PH850, PH8500, SX823-B, PH700, PH910, PC910, PH950, PH820 and PC820, PH9500, PC950, PC9500. May NOT work with other brands' meters because the temperature unit might be incompatible. The product is CE and RoHS certified, and is manufactured under an ISO 9001: 2015 certified quality system.