There is a good conductivity of this tester which is friendly to the environment and harmless to human body. It is filled with saturated kcl colloidal solution and can be used for printed circuit boards, ORP online testing of chromium containing wastewater. A tester is suitable for most ORP instruments and controllers with BNC Q9 connector. It is suitable for water sources, aquariums, hydroponics, laboratories, hot springs, swimming pools and other water systems. It is constructed of PC material. The diameter of each sticker is 17mm. The length of this product is 160mm. It is widely used for testing aqueous solutions. Item Name: Replace Probe Material: PC Features: Good Conductivity, Suitable for Most ORP Meters, Durable Model: ORP-101 Type: Laboratory Electrode Probe Type: Sensitive Glass Ball Bubble Range: 0~Plus or Minus 1999mV Accuracy: Plus or Minus 5mV Applicable Temperature Range: 5~70 Degree Celsius Electrode Potential: 245-270mv (15~30 Degree Celsius) Reference Electrode Internal Resistance: 10k Electrode Stability: Plus or Minus 8mv/24 Electrode Indication Electrode: Good Conductivity Electrode Plug Type: Q9 BNC: Integrity Size Details: Diameter: 17mm/0.67"(Approx.) Length: 160mm/6.3"(Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Replace Probe