The electrode is composed by the pH glass electrode and silver silver chloride reference electrode. It is the measuring element of pH meter, using to measure the pH of aqueous solution/water. Features: Widely used to test the the pH of aqueous solution/water. 100% brand new pH electrode probe. Great laboratory pH electrode probe. Suitable for most pH meter and controller with BNC connector. Apply in water sources, aquarium, hydroponics, laboratory, spas, swimming pools and other water systems. Specifications: Type: Laboratory Electrode Display: Digital Display Probe Type: Sensitive Crystal Ball Bubble Range: 0.00 ～ 14.00pH Accuracy: 0.01 Power Voltage: 5V Temperature Range: 0 ～ 80℃ Zero-point: 7±0.5(pH-201) / 7x±0.5(pH-151) (Optional) Color: Blue(pH-201) / Black(pH-151) Material: Polycarbonate Type of Electrode Plug: Q9 BNC: Upright Length of pH Electrode Line: Approx. 70cm / 27.5in Item Size: pH-201: Approx. 145 * 20 * 20mm / 5.7 * 0.8 * 0.8in (pH Electrode) pH-151: Approx. 155 * 20 * 20mm / 6.1 * 0.8 * 0.8in (pH Electrode) Item Weight: pH-201: Approx. 44.7g / 1.6oz pH-151: Approx. 47.3g / 1.7oz Package Size: Approx. 21 * 10.4 * 5cm / 8.3 * 4.1 * 1.9in Package Weight: pH-201: Approx. 85g / 3.0oz pH-151: Approx. 74g / 2.6oz Note: The difference between pH-201 and pH-151 is the Filling Liguid. The pH-201 Electrode comes without the Filling Liguid. The pH-151 Electrode comes with the Filling Liguid. Package List: 1 * pH Electrode 1 * Filling Liguid (ONLY pH-151)