The combined electrode is composed of needle indicating electrode and silver-chlorinated silver reference electrode. It is the measuring elements of ORP meter & water quality tester, using to measure the ORP of solution/water. Apply in water sources, aquarium, hydroponics, laboratory, spas, swimming pools and other water systems. Features: Widely used to test the the ORP of solution/water. Great laboratory ORP electrode probe. Suitable for most ORP meter and controller with BNC Q9 connector. Filled with saturated solution, used for printing circuit board, ORP on line measurement of containing chromium wastewater treatment. Material is environmental friendly with no harm to human body and great conductivity. Specifications: Type: ORP-101 Type: Laboratory Electrode Probe Type: Sensitive Crystal Ball Bubble Range: 0 ~ ±1999mV Accuracy: ±5mV Applicable Temperature Range: 5 ~ 70℃ Electrode Potential: 245-270mv (15~30℃) Internal Resistance of the Reference Electrode: ≤10kΩ Electrode Stability: ±8mv/24 Indicator Electrode of Electrode: Good Conduction Type of Electrode Plug: Q9 BNC: Upright Length of pH Electrode Line: . 70cm / 27.5in Item Size: . 155 x 20 x 20mm / 6.1 x 0.8 x 0.8in (ORP Electrode) Color: As Shown Material: plastic Package Contents: 3 x ORP Electrode Probe Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.